LIBRARY 

OF   THE 

UNIVERSITY  OF  CALIFORNIA. 
Oats 


FOUNDRY  PRACTICE 


A   TREATISE  ON    MOLDING  AND  CASTING 
IN  THEIR  VARIOUS  DETAILS 


BY 

JAMES  M.  TATE 

AND 

MELVIN  O.  STONE,  M.  E. 


PREPARED  FOR  THE  USE  OF  STUDENTS  IN  THE  COLLEGE  OF  ENGINEERING 
UNIVERSITY  OF  MINNESOTA 


MINNEAPOLIS 
THE  H.  W.  WILSON  COMPANY 

1904 


Copyright,  1904 

BY 

JAMES  M.  TATE 


INTRODUCTION 

In  administering  the  work  in  foundry  practice  at  the 
University  of  Minnesota,  the  want  of  a  good  text  book 
has  been  a  serious  disadvantage.  The  work  of  the  shop 
and  that  of  the  class  room  should  be  correlated — shop 
work  should  be  studied  and  discussed  in  the  class  room, 
and  examples  illustrating  the  various  principles  under- 
lying good  practice  should  be  worked  out  in  the  shop. 

While  there  have  been  some  excellent  books  written 
upon  the  subject  of  foundry  practice,  yet,  as  a  rule,  these 
have  been  written  with  the  needs  of  the  experienced 
molder  in  view  rather  than  those  of  the  beginner.  For 
this  reason  it  is  a  difficult  matter  to  teach  the  subject  so 
that  the  student  will  acquire  an  intelligent  understand- 
ing of  its  various  details.  The  nomenclature  and  shop 
phraseology  are  not  sufficiently  elementary  for  the  aver- 
age beginner  to  grasp  the  statement  presented,  and  much 
time  is  frequently  spent  in  explaining  an  author's  mean- 
ing. 

The  present  little  treatise  has  been  written  with  a  full 
knowledge  of  the  problems  involved  and  with  the  object 
of  lessening  some  of  the  difficulties  which  arise  in  teach- 
ing the  subject.  The  authors  are  both  men  of  wide  ex- 
perience in  foundry  practice  and  its  correlated  subjects. 
Mr.  Tate  is  an  experienced  pattern  maker,  who  has  been 
in  charge  of  the  pattern  shop  at  the  University  of  Min- 
nesota for  the  past  fifteen  years,  and  during  a  part  of 
this  time  he  has  also  had  charge  of  the  work  in  the  foun- 
dry. Mr.  Stone  is  a  graduate  of  the  University,  who  has 
given  especial  attention  to  foundry  work,  both  from  the 


129001 


iv  INTRODUCTION 

standpoint  of  the  chemist  and  from  that  of  the  molder. 

In  piesenting  this  work  on  foundry  practice,  the 
authors  realize  that  it  is  not  a  complete  treatise  on  the 
subject.  The  aim  has  been  to  produce  a  book  in  which 
the  principles  of  foundry  practice  are  set  forth  concisely 
and  clearly;  with  the  needs  of  the  engineering  student 
in  view  rather  than  those  of  the  practical  foundryman. 
To  this  end  numerous  examples  are  given  representa- 
tive of  the  different  kinds  of  molding,  and  it  is  believed 
that  the  simple  methods  used  in  illustrating  and  describ- 
ing the  various  operations  involved  and  the  reasons  there- 
for will  give  the  student  a  ready  knowledge  of  the  details 
of  molding  which  will  go  far  to  supplement  the  practical 
work  of  the  foundry,  which,  in  a  college  course,  must 
necessarily  be  limited. 

While  the  treatment  is  thus  somewhat  brief,  the  sub- 
ject matter  as  here  presented  is  intended  .o  cover  all 
ordinary  work  in  foundry  practice  including  both  brass 
and  iron  casting. 

A  glossary  of  foundry  terms  has  been  added,  as  it 
has  been  found  that  to  obtain  the  greatest  value  from  a 
work  of  this  character,  the  reader  must  become  familiar 
with  names  and  expressions  used  by  foundrymen,  for 
even  if  it  were  possible  to  eliminate  shop  expressions, 

it  would  be  undesirable  to  do  so. 

J.  J.  FLATHER. 

Professor  of  Mechanical  Engineering, 

Minneapolis,  Minnesota.  University  of  Minnesota. 

September,  IQOJ. 


The  authors  wish  to  acknowledge  their  indebtedness  to  Mr. 
E.  A.  Johnson,  Instructor  in  Foundry  Practice  at  the  University 
of  Minnesota,  and  also  to  other  foundrymen  for  information  and 
suggestions  received  in  the  preparation  of  their  work. 


TV   ; 


FOUNDRY    PRACTICE 

CHAPTER  I 

A  sand  suitable  for  molding  must  be  open  to  allow 
the  escape  of  gases  and  must  be  able  to  hold  a  given 
form  to  withstand  pressure  and  wash  of  the  metal. 
Such  a  sand  has  a  percentage  of  clay  or  binding  ma- 
terial which  will  hold  the  mass  together  firmly  when 
dampened  ai  1  compressed.  If  the  percentage  of  clay 
becomes  too  great,  the  sand  is  too  close  when  com- 
pressed, so  the  gases  cannot  pass  off ;  then  the  metal  will 
not  lie  quietly  against  the  face  of  the  sand. 

The  molding  sands  used  in  different  parts  of  the 
country  vary  greatly  in  their  composition.  Those  high 
in  clay  must  be  used  with  as  little  water  as  possible  and 
must  not  be  compressed  or  rammed  much  as  the  mold 
must  give  free  escape  for  gases  through  the  sand. 
The  coarse  sands  very  low  in  clay  may  require  much 
water  and  hard  ramming  in  order  to  form  a  satisfactory 
mold.  The  tempering  and  ramming  of  the  sand  must 
be  largely  gauged  by  the  nature  of  the  sand  the  molder 
has  at  hand. 

Tempering  the  sand  means  the  mixing  and  wetting 
of  the  sand  ready  for  making  a  mold.  It  is  otherwise 
known  as  cutting  over  the  sand. 

The  'sand  should  be  mixed  evenly  and  to  a  dampness 


2  FOUNDRY  PRACTICE 

such  that  it  will  stick  together  when  squeezed  in  the 
hand,  but  not  so  wet  as  to  show  moisture  or  dampen 
the  hand.  The  sand  pile  should  be  opened  out  so  that 
there  will  be  no  holes  in  which  the  water  will  accumu- 
late. The  water  should  then  be  thrown  over  the  sand 
in  thin  sheets  by  swinging  the  pail  with  the  bottom 
slightly  ahead  of  the  top.  In  this  manner  the  water  is 
distributed  evenly  and  does  not  cause  mud  in  spots.  If 
the  sand  is  wet  excessively  in  spots,  as  by  throwing  the 
water  on  the  pile  in  a  body,  it  requires  much  more  shov- 
elling to  obtain  an  even  temper,  hence  loss  of  time.  The 
sand  should  then  be  shovelled  over  in  order  to  mix 
thoroughly.  The  shovelling  should  be  done  so  as  to 
scatter  the  sand  when  casting  it  from  the  shovel.  This 
is  accomplished  by  giving  the  handle  of  the  shovel  a 
twist  just  as  the  sand  is  leaving  it.  When  wishing  to 
throw  the  sand  to  a  distant  point,  it  should  be  allowed 
to  leave  the  shovel  in  a  solid  mass,  but  this  does  not  mix 
it  evenly.  In  mixing,  a  space  should  always  be  kept  be- 
tween the  pile  from  which  the  sand  is  taken  and  the 
one  to  which  it  is  thrown.  If  this  is  not  observed  some 
of  the  sand  will  not  be  thoroughly  mixed.  After  the 
sand  has  been  shovelled  over  once  it  seldom  is  found 
to  be  mixed  thoroughly,  which  makes  it  preferable  to 
cut  it  over  from  two  to  three  times.  All  the  water 
necessary  for  the  proper  tempering  should  be  put  on 
before  shovelling  over  the  sand  the  last  time.  When 
trying  to  find  whether  the  sand  needs  more  water  or 
not  the  hand  should  be  forced  into  the  pile  to  get  some 
sand  from  the  interior  from  which  to  determine  its 
temper.  This  should  be  done  at  several  points.  The 
sand  from  the  interior  from  which  to  determine  its 
that  in  the  heap.  When  only  a  little  more  water  is 


FOUNDRY  PRACTICE  3 

necessary  it  should  be  sprinkled  on  by  throwing  the 
water  from  the  pail  with  the  hand. 

The  molder  or  helper  should  learn  to  shovel  either 
right-  or  left-handed,  so  as  to  be  able  to  take  either 
side  of  the  heap  when  working  'with  an  assistant. 

The  riddle  is  the  sieve  used  for  sifting  the  sand. 
Its  meshes  range  from  2  to  the  inch,  to  16  or  32  per 
inch.  They  are  numbered  according  to  the  number 
of  meshes  per  inch,  as  a  No.  2  riddle  means  one  having 
^2  in.  meshes,  a  No.  4  has  l/\.  in.  meshes,  a  No.  16  has 
Vic  m-  meshes,  etc.  In  some  places  the  riddles  having 
the  mesh  finer  than  l/%  in.  are  called  sieves. 

In  riddling  sand  by  hand,  the  riddle  should  be  held 
loosely  in  the  hand  and  carried  by  the  fingers  so  that 
the  palm  of  the  hand  will  strike  the  rim  as  it  is  cast 
from  side  to  side.  Hitting  the  rim  of  the  riddle  in  this 
way  jars  loose  the  sand  that  sticks  to  the  riddle,  keeps 
the  meshes  open  better,  and  allows  the  sand  to  pass 
through  more  freely.  By  practice  in  holding  the  riddle 
in  this  manner,  a  rocking  swing  may  be  obtained  which 
jars  the  riddle  at  each  turn  and  carries  but  very  little 
weight  on  the  fingers.  It  is  often  found  of  advan- 
tage, especially  in  fine  riddles,  to  put  some  irons  in  with 
the  sand,  as  gaggers,  etc.  These  irons  scrape  the  wires 
clean  and  add  to  the  jarring  of  the  riddle. 

When  not  in  use,  the  riddle  should  always  be  hung 
up  on  a  nail  or  placed  on  the  sand  heap  with  the  screen 
up.  If  left  with  the  screen  resting  on  the  sand,  the 
meshes  -become  clogged,  thus  hindering  the  passage  of 
the  sand  through  the  screen. 

There  are  many  forms  of  mechanical  sand  sifters. 
The  two  representative  forms  of  pneumatic  sifters  are 


4  FOUNDRY  PRACTICE 

shown  in  Figs.  93  and  96,  while  the  belt-driven  sifters 
are  shown  in  Figs.  98  and  99. 

Facing  sand  is  placed  next  to  the  pattern  in  making 
a  mold,  in  order  that  the  sand  will  peel  or  part  from 
the  casting  freely  and  leave  a  smooth  surface.  Facing 
sand  contains  a  percentage  of  sea  coal  and  usually  new 
sand,  dependent  upon  the  kind  of  work  for  which  it  is 
to  be  used. 

The  percentage'  of  sea  coal  varies  greatly,  depending 
upon  the  thickness  of  metal  and  type  of  casting.  The 
limits  are  i  part  of  sea  coal  to  2  parts  of  sand,  and  i 
part  of  sea  coal  to  16  to  20  parts  of  sand.  The  limiting 
proportions  are  very  seldom  used.  The  usual  propor- 
tions are  from  I  to  6,  to  i  to  14  of  sand,  depending  on 
the  thickness  of  the  metal.  When  the  metal  is  thinner 
than  y2  in.  no  facing  is  necessary.  Better  and  smoother 
castings  are  obtained  in  this  case  by  using  heap  sand 
riddled  through  a  fine  riddle  onto  the  pattern.  For 
metal  between  y2  in.  and  i  in.  the  proportion  should 
be  about  i  part  of  sea  coal  to  12  or  14  parts  of  sand; 
between  i  in.  and  2  in.,  i  part  of  sea  coal  to  8  or  10  parts 
of  sand;  above  2  in.,  i  part  of  sea  coal  to  6  or  8  parts  of 
sand. 

The  sand  used  in  the  facing  may  also  vary  in  its 
proportion  of  new  and  old  sand.  This  is  dependent  up- 
on the  sand  used.  The  most  general  proportion  is  i 
part  of  new  sand  to  from  3  to  5  parts  of  old  sand. 
Greater  percentages  of  new  sand  may  be  used  on 
heavy  work.  The  limiting  case  is  a  facing  made  of 
entirely  new  sand  for  the  cope  of  very  heavy  work. 

It  is  not  always  the  thickness  of  the  casting  that 
regulates  the  strength  of  the  facing  sand.  There  are 
many  other  things  to  be  considered :  ( i )  whether  the 


FOUNDRY  PRACTICE  5 

casting  is  to  be  poured  with  hot  or  dull  iron;  (2)  the 
distance  of  some  parts  of  the  mold  from  the  gate;  (3) 
the  time  it  will  take  the  mold  to  become  filled  with  iron ; 

(4)  whether  the  metal  is  running  over  flat  surfaces,  and 

(5)  is   covering  them   slowly   or   quickly.     Then   again, 
heavy    solid    castings    have    become   "cold-shot"   owing 
to  the  use  of  facings  that  were  weak  in  proportion  to 
the  casting,  caused  by  the   slow  rising  of  the  metal  in 
pouring.     Strong  facings  on  the  sides  of  a  mold,  where 
the  iron  enters  and  rises  slowly,  may  easily  cause  heav\ 
castings  to  be  "cold-shot."     Again,  the  square   corners 
of  castings  should,  in  general,  have  weaker  facings  than 
the   straight,   plain   surfaces.      The   lower  parts   of   deep 
molds  should  have  a  stronger  facing  than  the  upper  por- 
tion, because  the  metal  becomes  dull  while  rising  to  the 
top  of  the  mold.     If  the  facing  suitable   for  the  lower 
portion  were  used  at  the  upper,  the  casting  at  the  upper 
part  would  become  curly  or  partly  cold-shot  at  the  sur- 
face.    A  new  sand   without  mixture  will   require   more 
sea   coal   than    if   it   were    mixed    with    old   or    common 
heap  sand. 

A  thorough  mixing  of  the  facing  is  necessary.  If 
the  sea  coal  is  not  evenly  -mixed,  it  often  causes  the 
casting  to  be  streaked,  veined,  or  cold-shot. 

In  mixing  by  hand  it  is  almost  impossible  to  dis- 
tribute the  sea  coal  evenly,  therefore  it  is  important  that 
it  should  be  handled  several  times  in  order  to  come  as 
near  as  possible  to  a  thorough  mixture. 

In  mixing,  the  old  and  new  sand  should  be  kept  as 
dry  as  possible  when  shovelled  over  in  order  to  mix 
well.  The  sea  coal  is  added  while  the  sand  is  spread 
out  thin.  The  whole  is  cut  over  once  or  twice,  then  rid- 
dled through  a  No.  6  or  8  riddle.  It  is  then  tramped 


6  FOUNDRY   PRACTICE 

down  and  water  put  on  to  give  the  proper  temper,  as  in 
the  case  of  tempering  the  heap  sand.  It  is  again  cut 
over  to  mix  the  wet  and  dry  sand,  then  riddled  through 
a  No.  4  riddle.  It  is  now  ready  to  be  riddled  onto  the 
pattern.  The  mixture  should  always  be  riddled  twice, 
and  better  still,  three  or  four  times  It  is  best  to  use 
sand  quite  dry  to  start  the  mixture,  as  when  wet  the 
sea  coal  sticks  in  small  balls  and  does  not  mix  well. 
In  large  foundries,  the  facing  sand  is  mixed  by  a 


Fig.  i. 

facing  machine  which  gives  a  mixture  of  exact  propor- 
tions and  more  thoroughly  mixed  than  can  be  done  by 
hand. 

The  frame  in  which  a  mold  is  made  is  called  a  flask. 
It  is  composed  of  two  or  more  parts.  The  bottom  part 
is  called  the  drag  or  nowel,  the  top  part  is  called  the 
cope,  and  the  intermediate  parts,  when  used,  are  called 
the  cheek.  Flasks  are  made  of  wood  or  iron. 

The    form    of    flask    used    for    small    patterns    when 


FOUNDRY   PRACTICE  7 

the  pressure  of  the  metal  is  very  little,  is  represented  in 
Fig.  i.  These  are  called  snap  flasks.  They  are  hinged 
at  one  corner  and  fasten  at  the  diagonal  corner  with  a 
snap.  The  mold  is  rammed  in  the  flask  and  when  ready 
for  pouring  the  flask  is  unsnapped  and  removed. 
Thus  many  molds  may  be  made  with  a  single 
flask.  Before  casting,  a  frame  the  same  size  as  the 
flask  is  placed  around  the  body  of  sand  and  a  weight 
is  placed  on  top  to  prevent  straining  the  mold  when 
under  pressure. 

Small  flasks  up  to  14  in.  square  may  best  be  made 
of  iron,  without  bars  in  the  cope.  Those  larger  may  be 
of  either  wood  or  iron  to  suit  the  style  of  work  to  be 
put  in  the  flask.  When  the  flask  is  for  a  special  pattern 
and  is  to  be  used  for  that  only,  an  iron  flask  will  give 
the  better  service  and  is  far  cheaper.  When  for  general 
patterns,  the  wood  flask  has  many  advantages.  The 
bars  may  be  fitted  to  a  pattern  in  wood  with  little  time 
or  expense,  and  for  a  class  of  small  work  up  to  40  in. 
square,  may  be  made  of  sufficient  strength.  Larger 
flasks  are  made  of  wood  having  bolts  or  iron  bars  for 
stiffening  the  cope.  When  but  a  single  casting  is  de- 
sired, even  to  very  large  castings,  the  flask  may  be 
more  cheaply  made  with  a  wood  frame  and  iron  bars 
than  entirely  of  iron. 

In  manufacturing  shops  having  a  fixed  line  of  pat- 
terns, the  iron  flask  is  of  great  value.  The  first  cost  is 
more  than  that  of  a  wood  flask,  but  the  durability  far  ex- 
ceeds that  of  wood.  The  bars  are  shaped  to  suit  the  pat- 
tern, and  they  remain  so ;  while  a  wood  bar  burns  out  and 
the  joint  of  the  wood  flask  burns  away  leaving  holes 
which  may  cause  a  run-out,  thus  losing  the  casting.  The 
iron  flask  is  much  heavier  to  handle,  but  it  may  be  fitted 


8  FOUNDRY  PRACTICE 

so  as  to  require  less  anchoring  in  the  sand,  as  gaggers 
and  soldiers  which  would  be  required  in  a  wood  flask ; 
thus  the  time  saved  in  molding  will  more  than  equal 
the  extra  help  necessary  to  handle  the  flask.  Large 
flasks  to  hold  castings  as  cylinders,  engine  girders,  bed 
castings,  etc.,  and  flasks  to  be  used  many  times,  should 
be  made  of  iron  and  well  braced.  They  are  then  ready 
at  all  times  and  may  be  used  without  loss  of  time  in 
repairs. 

To  point  out  the  saving  resulting  from  the  use  of  a 
flask  instead  of  bedding  the  pattern  into  the  pit,  the 
relative  time  required  for  making  a  girder  casting 
in  the  two  ways  may  be  cited.  Before  the  flask  was 
made  to  hold  the  pattern,  it  was  bedded  into  the  pit  with 
a  cope  to  cover  it.  It  required  a  time  equivalent  of  14 
days,  with  a  molder  and  helper  to  complete  and  cast 
the  mold.  After  the  flask  was  made  so  the  pattern  was 
rammed  in  the  drag  and  turned  over,  it  required  a  time 
equivalent  of  9  days  for  a  molder  and  helper  to  make 
the  same  casting. 

Holders'  tools  vary  greatly  with  the  general  type  of 
work  that  the  molder  is  making.  The  number  of  tools 
necessary  for  a  molder  on  a  particular  type  of  work- 
may  be  three  or  four,  while  on  intricate  work  many  tools 
may  be  required.  There  are  tool  manufacturers  who 
can  furnish  tools  of  nearly  any  size  or  shape  that  a 
molder  may  desire.  The  more  common  forms  are  shown 
in  Fig.  2.  These  are  used  for  nearly  all  classes  of  work 
and  are  made  in  many  sizes  as  desired.  No.  i  is  a  round 
point  finishing  trowel;  No.  2,  a  square  trowel.  No.  3 
is  a  lifter  for  removing  sand  from  deep  and  narrow 
parts  of  a  mold.  No.  4  is  a  flange  and  bead  tool  for 
slicking  special  round  surfaces.  Nos.  5  and  6  are  two 


FOUNDRY   PRACTICE  9 

forms  of  double-end  slickers  which  represent  the  general 
forms  out  of  greatly  varying  forms  of  such  tools.  No. 
5  has  an  oval  slick  at  one  end  with  the  spoon  slick  at 
the  other.  No.  6  has  the  square  and  heart  slicks.  Nos. 
7,  8,  and  9  show  corner  slicks  of  which  No.  7  is  for 
round  corners,  No.  8  for  square,  and  No.  9  for  inside 
corners.  Nos.  10  and  n  are  pipe  slicks  for  cylindrical 
surfaces.  No.  10  has  the  square  ends,  while  No.  n  has 
the  safe  end  for  a  corner  slick. 


Fig.    2. 


The  success  of  making  the  mold  and  obtaining  a 
good  casting  is  dependent  mainly  upon  the  manner  of 
ramming  the  sand  to  form  the  mold.  Hard  spots  in 
the  sand  cause  scabs,  and  soft  spots,  a  swell.  Uneven- 
ness  of  ramming  causes  similar  unevenness  in  the  cast- 
ing. 

In    ramming    the    drag,    the    flask    should    be    filled 


io  FOUNDRY   PRACTICE 

to  a  depth  of  from  5  to  6  inches,  ramming  first  around 
the  edge  of  the  flask,  then  next  to  the  pattern,  and, 
lastly,  the  portion  between,  using  the  pein.  On  small 
castings,  it  is  rarely  necessary  to  ram  the  sand  over  the 
pattern.  The  pein  or  the  butt  of  the  rammer  should 
never  strike  within  an  inch  of  the  pattern,  as  it  will 
cause  a  hard  spot  at  that  point. 

In  deep  molds,  the  succeeding  rammings  should  be 
done  by  filling  in  loose  sand  to  the  depth  of  about  6 
inches,  and  ramming  first  with  the  pein  then  with  the 
butt  in  order  to  give  the  mold  the  proper  degree  of  hard- 
ness. 

In  ramming  the  drag,  either  the  pein  or  the  butt  may 
be  used  as  soon  as  the  pattern  is  well  covered  so  that  the 
ramming  is  not  near  the  pattern.  It  is  of  advantage  to 
tramp  the  sand  with  the  feet  before  butting,  as  that 
more  quickly  compresses  it  to  a  moderate  hardness  and 
facilitates  the  butt  ramming. 

In  ramming  the  rim  of  a  pulley,  the  rammer  should 
be  directed  away  from  the  pattern  to  prevent  scabbing 
the  rim. 

The  larger  the  pattern,  the  harder  the  sand  may 
be  rammed.  When  of  a  depth  to  give  a  great  pressure 
on  the  bottom,  the  sand  must  be  rammed,  harder  to  hold 
the  pressure  and  prevent  the  cracking  of  the  surface 
causing  roughness  sometimes  called  "whiskers." 

On  patterns  of  the  round  column  type,  the  sand  may 
be  rammed  very  much  harder  than  in  other  cases,  if  the 
metal  is  to  be  thick.  It  is  very  important  to  have  these 
rammed  evenly,  as  unevenness  will  cause  defects  in  the 
casting,  even  though  it  is  not  of  a  hardness  at  any 
point  which  would  be  detrimental  were  the  entire  mold 
of  that  hardness. 

The   softer  the   sand   can  be   left  an  1   still   hold   the 


FOUNDRY   PRACiiCE  11 

casting  in  proper  form,  the  less  is  the  liability  of  losing 
the  casting.  The  sand  must  be  hard  enough  to  hold  its 
shape,  but  after  that  the  risk  of  loss  in  casting  is  in- 
creased as  the  hirdness  is  incre:.sed. 

In  ramming  the  cope  where  there  are  no  bars,  the 
sand  is  filled  in  to  a  depth  of  about  6  in.  and  rammed 
around  inside  the  flask,  then  the  remaining  portion  is 
rammed  evenly  with  the  pein.  The  butt  should  not  be 
used  in  the  cope  until  the  entire  flask  is  filled,  then  the  last 
ramming  on  top  is  done  with  the  butt.  If  the  butt  is 
used  before  this,  it  causes  a  hard  surface  so  that  the 
sand  does  not  unite  in  the  succeeding  ramming  and  is 
liable  to  fall  out  when  the  cope  is  turned  over.  When 
the  cope  has  bars,  each  division  enclosed  by  the  bars 
is  rammed  separately  as  a  small  cope,  but  all  the  divis- 
ions must  be  of  an  even  hardness.  The  successive  ram- 
mings  are  made  by  filling  in  about  6  in.  at  a  time  and 
ramming  with  the  pein. 

The  proper  manner  of  holding  the  floor  rammer 
while  ramming  is  to  grip  the  rod  connecting  the  pein 
and  butt  with  one  hand  above  the  other.  Never  hold 
the  rammer  with  one  hand  on  top  of  the  upper  end  of 
the  rammer,  as  it  will  jar  the  operator  and  it  is  harder  to 
do  good  ramming  while  in  this  position. 

The  proper  venting  of  a  mold  is  of  as  great  impor- 
tance as  any  part  of  the  process.  If  at  any  point  the 
venting  is  insufficient  to  carry  off  the  gases,  the  metal 
will  blow  and  spoil  the  casting. 

The  air  in  the  mold,  when  the  metal  is  being  poured, 
must  be  able  to  escape.  This  is  provided  for  in  some 
cases  by  the  riser,  but  often  the  vents  are  depended  upon 
for  this  purpose.  The  water  in  the  sand  is  heated  to 
steam  and  must  escape  through  the  sand.  The  contin- 


12  FOUNDRY   PRACTICE 

tied  addition  of  sea  coal  in  the  facing  and  flour  and 
plumbago  in  the  mold  increases  the  formation  of  gases 
when  the  metal  comes  in  contact  with  the  face  of  the 
mold.  If  these  can  not  escape  into  the  sand,  they  force 
an  opening  through  the  molten  metal  which  is  known 
as  blowing.  To  enable  the  gases  to  pass  through  the 
sand,  the  mold  must  be  properly  vented.  Some  sands 
are  so  coarse  and  open  that  they  require  much  less 
venting  than  others  which  are  fine  and  close  in  texture. 

Small  and  thin  castings,  rammed  lightly,  require  no 
venting.  In  casting  heavy,  thick  plates  the  drag  must 
be  well  vented,  but  the  cope  does  not  require  much  vent- 
ing, although  it  is  always  best  to  vent  it.  In  venting 
any  plain  casting,  the  size  of  vent  wire  is  mainly  depend- 
ent upon  the  depth  of  sand  to  be  vented.  For  flasks 
up  to  12  in.  in  depth,  V$  in.  wire  serves  well.  The 
exact  size  of  wire  used  is  unimportant,  so  that  the  vent- 
ing is  close  enough  to  give  free  escape  of  the  gases. 
The  vent  wire  should  not  strike  the  pattern  or  scrape 
along  a  side,  as  it  forms  holes  that  the  metal  may  flow 
through  and  allows  the  metal  to  stop  up  the  vent,  which 
gives  the  same  condition  as  though  there  were  no  vent. 
The  bottom  board  should  be  put  on  the  drag  and 
rubbed  to  a  bearing,  then  removed,  and  the  surface 
creased  crosswise  by  striking  with  the  corner  of  a  stick- 
to  reach  the  width  of  the  drag,  then  the  drag  vented 
The '  creases  form  openings  through  which  the  gases- 
may  escape  when  the  drag  is  turned  over. 

For  small  castings,  the  cope  should  be  vented  through 
almost  to  the  pattern  to  give  free  escape  for  the  gases 
and  air.  For  larger  castings  it  is  often  advisable  to 
leave  a  layer  o<f  2  to  3  inches  next  to  the  pattern  with- 
out vents.  This  does  not  give  free  escape  for  the  air ; 


FOUNDRY   PRACTICE  13 

thus  a  pressure  can  be  maintained  within  the  mold  while 
pouring  which  prevents  the  drawing  down  of  the  cope. 
Many  molds  have  enclosed  bodies  of  sand  which  do 
not  have  free  vent  connections  with  the  top  or  bottom 
of  the  flask,  as  anchors  in  pulley  molds,  center  parts 
in  three-part  flasks,  or  large  green  sand  cores.  The 
vent  must  be  led  to  some  convenient  point  where  an 
opening  is  left  through  the  cope  for  the  gases  to  escape. 
A  gutter  may  be  cut  around  the  surface  of  the  body  of 
sand  about  3  or  4  inches  from  the  pattern  and  connected 
to  the  vent  opening.  Slant  vents  from  the  gutter  will 
give  free  vent  to  the  gases. 

In  some  molds  there  are  pocket?  having  metal  on  all 
sides  but  one.  The  vent  must  be  led  away  through  this 
side  and  this  very  freely.  When  the  pocket  is  small, 
a  vent  rod  may  be  laid  in  it,  and  slant  vents  leading  to 
the  pattern  give  the  necessary  relief.  When  the  pocket 
is  of  large  size,  it  is  not  safe  to  depend  on  the  slanting 
vent.  In  these  cases  the  gases  are  collected  by  a  coke 
or  cinder  bed  laid  in  the  pocket  and  led  to  the  outside 
by  a  vent  pipe  or  large  vent  rod. 

In  some  patterns,  as  columns,  the  vent  may  be  led 
off  at  the  parting  instead  of  through  the  bottom  of  the 
drag.  After  the  flask  is  rammed  up  and  the  cope  re- 
moved, vents  are  made  under  the  pattern  from  the  sur- 
face of  the  drag  at  a  distance  of  about  2  inches  apart. 
These  are  led  to  the  outside  by  cutting  or  scratching  a 
small  gutter  in  the  surface  from  the  vent  to  the  flask. 
Pit  molds  and  all  floor  molds  must  be  provided  with 
a  cinder  bed  located  about  il/2  or  2  feet  below  the  cast- 
ing to  provide  for  the  escape  of  the  gases  of  the  lower 
half  of  the  mold.  The  cinder  bed  is  connected  to  the 
surface  by  vent  pipes  which  give  free  passage  for  the 


14  FOUNDRY   PRACTICE 

gases.  Very  deep  molds  may  have  cinder  beds  located 
at  different  levels  around  the  mold.  The  gases  are 
led  to  the  cinder  bed  by  freely  venting  the  mold  so  that 
the  wire  strikes  the  bed. 

Surface  molds  require  much  better  venting  than 
those  covered  with  a  cope,  as  the  metal  gives  no  pres- 
sure except  its  weight;  thus  it  can  not  force  the  gases 
against  much  resistance.  Small  surface  molds  may  not 
require  venting,  if  the  sand  is  rammed  only  enough  to 
prevent  the  metal  cutting  when  poured.  Larger  molds 
must  be  provided  with  a  cinder  bed  and  well  vented 
from  the  mold  and  to  the  surface. 

When  two  parts  of  a  flask  are  to  be  lifted  apart  after 
the  sand  is  rammed,  it  is  necessary  to  make  the  surface 
at  the  parting  so  that  the  two  bodies  of  sand  will  not 
knit  together  but  separate  freely  when  the  flask  is 
opened.  In  order  to  ensure  the  parting,  the  surface  of 
the  sand  must  be  slicked  smooth  after  making  the  sur- 
face harder  than  the  other  part  of  the  mold  and  cov- 
ered with  a  parting  sand. 

When  the  drag  is  turned  over  and  the  follow  board 
is  removed,  the  surface  is  gone  over  with  the  hand  and 
sand  tucked  in  wherever  so>ft  spots  are  found.  The 
sand  is  then  cut  away  to  the  parting  of  the  pattern  or 
to  the  surface  of  the  part.  A  thin  coat  of  sand  is  then 
riddled  onto  this  surface  and  the  whole  slicked  to  a 
smooth  face.  The  additional  sand  compacts  the  surface 
to  a  harder  shell  and  should  not  be  easily  broken  by  the 
ramming  of  the  sand  that  rests  on  this  parting.  This 
slicking  must  not  be  carried  to  an  extent  of  causing  an 
extra  hard  or  bricklike  face,  as  this  will  cause  defective 
castings  similar  to  hard  spots  in  ramming. 

Parting  sand  is  put  over  the  surface  in  a  thin  coat- 


FOUNDRY   PRACTICE  15 

ing.  All  parts  of  the  sand  must  be  covered,  for  any 
spots  left  bare  will  stick  and  not  give  a  clean  part. 
Parting  sand  used  for  this  purpose  may  be  any  fine  dry 
sharp  sand,  very  fine  cinders,  or  burnt  core  sand  from 
the  burned  cores  in  the  castings.  This  sand  is  most 
convenient  on  all  plane  surfaces  and  where  the  slope 
is  not  so  great  that  it  will  not  stay  on  the  entire  face. 
In  cases  where  the  dry  sand  will  not  cover  the  surface 
well,  wet  sharp  sand  makes  a  good  part.  The  fine  sharp 
sand  is  dampened  until  the  sand  sticks  together,  then  it 
is  put  onto  the  surface  with  the  hand  or  slicked  on  with 
a  tool.  It  often  helps  to  dust  a  little  dry  parting  sand 
over  the  wet  sand  after  it  is  on  the  surface,  as  the  wet 
sand  sometimes  sticks  when  the  surfaces  are  lifted 
apart. 

Parting  sand  and  burnt  core  sand  make  molding 
sand  coarse  and  weak  as  it  loses  its  strength  to  hold  a 
form  when  rammed.  Too  much  of  the  parting  sand  will 
spoil  the  sand  for  the  mold. 

Gates  are  the  openings  through  which  the  metal  en- 
ters the  mold.  The  location  of  the  gate  makes  a  great 
difference  in  the  resulting  casting.  A  mechanic  can 
show  his  ability  in  gating  properly  more  readily  than 
in  any  other  part  of  the  mold.  Many  castings  are  lost 
just  because  the  molder  is  not  particular  enough  in 
locating  and  cutting  his  gates. 

All  plain  castings  having  about  an  even  thickness, 
and  that  greater  than  the  runners,  are  gated  at  the  side 
and  present  little  or  no  difficulty.  As  thin  plates  having 
runners  heavier  than  the  casting  set  sooner  than  the 
runner,  they  can  not  be  gated  at  the  side  because  when 
the  runner  cools  the  casting  will  be  strained  or  warped. 
A  good  form  of  gate  in  such  cases  is  that  known  as  the 


16  FOUNDRY  PRACTICE 

bridge  gate,  having  a  basin  above  which  is  connected 
to  the  mold  by  a  long  narrow  opening  through  which 
the  metal  enters.  This  gate  is  easily  broken  off  and 
leaves  the  casting  straight. 

On  any  casting  having  ribs  running  from  the  side 
to  the  bottom,  the  metal  shouM  be  directed  lengthwise 
of  the  rib,  in  preference  to  flowing  over  the  edge  of  the 
sand,  as  there  will  be  less  danger  of  the  metal  cutting 
the  sand. 

The  thin  parts  of  a  casting  should  be  filled  as  quickly 
as  possible  after  the  metal  starts  into  them.  A  casting 
having  heavy  and  light  parts  should  be  gated  so  that 
the  thin  parts  can  be  filled  quickly,  and  not  rise  slowly, 
as  when  filling  both  the  heavy  and  light  parts  at  the 
same  time.  If  the  gate  is  placed  on  a  thin  part  so  that 
the  metal  flows  over  the  surface  of  the  mold  into  the 
heavy  portion  of  the  casting,  the  inflowing  metal  will 
become  cooled  and  as  it  rises  into  the  thinner  parts  it 
is  liable  to  become  cold-shot  or  form  seams,  which 
spoils  the  casting. 

The  gate  must  be  so  located  that  the  metal  will  not 
flow  over  a  sharp  bead  of  sand  which  may  be  washed 
away.  This  difficulty  is  sometimes  overcome  by  use 
of  the  horn  gate. 

The  common  use  of  a  riser  on  small  castings  is  to 
allow  the  air  and  gases  to  pass  out  of  the  mold  while 
it  is  being  poured.  The  dirt  carried  into  the  mold  by 
the  inflow  of  metal  is  carried  on  the  surface  of  the  iron, 
and,  as  the  metal  rises  in  the  riser,  the  dirt  is  floated  out 
of  the  casting. 

On  large  castings  or  those  whose  shrinkage  is  great, 
the  riser  is  made  large  so  as  to  supply  metal  to  feed 
the  shrinkage.  The  riser  must  be  large  enough  so  that 


FOUNDRY   PRACTICE  17 

it  will  not  freeze  until  the  casting  itself  has  set.  If 
the  shrinkage  is  not  thus  taken  care  of,  the  casting  is 
liable  to  have  shrink-holes  in  it. 

The  location  of  the  riser  for  small  castings  is  not  of 
so  great  importance,  although  it  is  best  to  have  it  where 
the  dirt  is  most  liable  to  accumulate.  In  castings  where 
it  acts  as  a  feeder,  it  should  be  connected  as  near  as  pos- 
sible to  the  heaviest  part  of  the  casting.  In  castings  of 
such  a  size  as  to  require  feeding,  the  riser  is  placed  over 
the  heaviest  part  of  the  casting  and  it  becomes  a  feed- 
ing head.  In  this  case  the  casting  is  fed  by  a  feeding 
rod  which  keeps  the  riser  from  freezing  until  the  casting 
sets.  This  process  is  called  feeding,  or  churning,  the 
casting.  In  some  cases,  as  cannons,  or  rolls  which  are 
cast  on  end,  the  casting  is  made  longer  than  that  de- 
sired and  the  end  turned  off  in  the  lathe.  The  extra 
length  takes  the  place  of  the  feeding  head  and  is  known 
as  a  sinking  head.  In  this  case  the  casting  does  not  re- 
quire feeding. 

Some  foundries  making  castings  only  up  to  the  me- 
dium weight  never  make  use  of  the  feeding  rod  but, 
instead,  depend  on  the  riser  as  a  sinking  head  and  pour 
the  iron  as  dull  as  it  can  be  run  into  the  mold.  These 
castings  are  often  unsatisfactory  and  frequently  have 
shrink-holes  in  their  upper  surface. 

A  skim  gate  is  an  arrangement  of  gates;  risers,  and 
runners  leading  to  a  mold,  whereby  a  supply  of  pure 
metal  may  be  obtained,  and  the  impurities  remain  in 
the  riser.  An  ordinary  skim  gate  may  be  constructed 
as  in  Fig.  3.  The  molten  metal  enters  through  the  pour- 
ing gate  a  and  flows  through  the  runner  c  into  the  riser 
b.  The  impurities  come  to  the  top  in  the  riser  while 
the  pure  metal,  being  heavier,  remains  at  the  bottom  and 


i8 


FOUNDRY  PRACTICE 


flows  out  through  the  runner  d  into  the  mold  e.  The 
arrangement  of  the  gate,  runner,  and  riser,  as  shown 
in  the  plan  view,  is  for  the  purpose  of  giving  the  metal 
a  rotary  motion  while  rising  in  the  riser  b.  This  is 
intended  to  aid  the  separation  of  the  impure  metal, 
sand,  and  dirt  from  the  pure  metal.  The  runner  d  is  be- 
low the  level  of  the  runner  c.  The  cross  section  of  c 


::?'v";V  Drag  \-V  ;.••.;'•/;."•*';:;•;' 


Mo/d 


Fig.  3- 

must  be  greater  than  that  of  d  to  ensure  keeping  the 
riser  b  full  while  the  metal  is  being  poured.  Good  re- 
sults and  sound  castings  are  obtained  by  the  use  of  this 
arrangement  for  the  gate. 

The  top  gate  with  the  pouring  basin  shown  in  Fig. 
47  forms  a  good  skimming  gate.  It  is  upon  the  prin- 
ciple that  the  pure  metal  being  heavier  flows  into  the 
mold  from  the  bottom  of  the  basin,  while  the  impurities 


FOUNDRY  PRACTICE 


remain  at  the  top.  In  pouring,  the  basin  must  be  kept 
full  so  that  the  metal  enters  the  gate  from  the  bottom 
instead  of  from  the  surface  of  the  metal  in  the  basin. 
The  only  chance  for  dirt  to  be  carried  into  the  mold  is 
when  the  metal  first  starts  before  the  basin  is  full  and 
forces  sand  and  dirt  into  the  mold. 

The  preceding  arrangements  are  formed  by  the  gate 
sticks,  gate  cutter,  and  trowel.     A  very  convenient  de- 


Fig.  4. 

vice  for  forming  a  skim  gate  is  by  use  of  a  pattern  as 
shown  in  Fig.  4.  This  pattern  is  rammed  up  in  the 
drag  with  the  pattern  to  be  molded.  The  portion  marked 
A  is  a  core  print.  After  drawing  the  pattern,  the  core 
B  is  placed  in  the  prints.  The  metal  entering  at  C  is 
given  a  rotary  motion  under  the  riser  placed  at  D  where 
the  impurities  rise.  The  pure  metal  flows  under  the  core 
into  the  mold  through  E. 


20  FOUNDRY   PRACTICE 

There  are  few  things  in  connection  with  making  a 
mold  that  are  of  greater  importance  than  the  construc- 
tion of  the  pouring  basin,  gate,  runner,  and  riser.  Skill 
is  necessary  to  be  thoroughly  successful  in  their  con- 
struction. In  these,  the  washing  or  cutting  away  of 
the  sand  by  the  force  of  the  falling  metal  is  most  likely 
to  occur.  When  this  takes  place,  great  damage  is  likely 
to  result  to  the  casting.  If  the  molder  should  slight 
any  other  portion  of  the  mold,  he  may  still  get  a  cast- 
ing which  would  pass  inspection ;  but  any  neglect  or 
ignorance  in  the  construction  of  the  pouring  basin,  gates, 
or  runners  will  usually  spoil  the  casting.  When  the 
sand  in  these  cuts  or  breaks,  the  loose  sand  flows  with 
the  metal  into  the  mold  and  causes  a  dirty  casting. 
Great  care  should  be  taken  to  have  the  sand  well  tem- 
pered for  the  construction  of  a  pouring  basin.  To  make 
a  reliable  pouring  basin,  the  sand  should  be  rammed 
evenly  into  the  box  or  frame,  and  the  basin  cut  out  with 
the  trowel.  This  ensures  an  even  solidity  to  the  sand 
and  prevents  cutting  or  washing. 

Gaggers  are  L-shaped  irons  used  by  molders  to  an- 
chor the  sand  into  the  flask.  The  lower  end  of  the 
gagger  is  called  the  "heel,"  and  varies  in  length  from 
2  to  6  inches  to  suit  different  conditions.  The  other 
portion  of  the  gagger  may  be  of  any  length  to  suit 
the  depth  of  flask  in  which  it  is  used.  Some  gaggers 
are  made  with  a  short  hook  bent  at  the  upper  end  for 
hooking  over  the  bar  of  the  cope  to  ensure  firmness  in 
lifting.  They  are  made  either  of  wrought  or  cast  iron. 
Wrought  iron  is  preferable,  for  in  some  places  it  is 
necessary  to  bend  the  gagger  to  suit  the  particular  con- 
ditions. 

Gaggers  are  of  great  assistance  in  securing  sand  into 


FOUNDRY   PRACTICE  21 

a  flask  and  in  many  cases  are  indispensable.  To  ob- 
tain a  good  lift  in  a  cope  without  gaggers,  requires  the 
bars  to  be  in  very  good  condition  and  to  come  near  to  the 
parting.  With  gaggers,  the  sand  may  be  anchored  with- 
out the  bars  being  new  for  each  special  casting. 

The  strength  with  which  the  gaggers  hold  the  sand 
depends  upon  the  manner  in  which  they  are  set.  When 
properly  set  they  hold  with  great  efficiency.  When  set 
wrongly  they  only  add  weight  tending  to  pull  the  sand 
down  or  cause  a  drop-out. 

The  gagger  should  be  so  placed  that  the  heel  comes 
near  to  the  parting  of  the  sand  to  be  lifted  and  should 
be  parallel  to  it.  The  length  of  the  gagger  should  coine 
against  the  bar  or  frame  of -the  flask  as  shown  at  A 
in  Fig.  29,  page  68.  It  is  not  always  necessary  to  have 
the  gagger  stand  vertical,  although  that  is  the  best 
position.  Odd  slopes  may  often  be  accommodated  bv 
slanting  the  gagger  or  bending  the  heel.  Oftentimes 
mistakes  are  made  in  setting  gaggers  improperly  and 
cause  trouble.  A  few  ways  of  setting  gaggers  so  they 
do  not  hold  as  desired  are  shown  in  Fig.  29.  At  B 
the  gagger  will  hold  the  sand  above  all  right,  but  the 
sand  below  is  liable  to  drop.  In  this  cope  the  desired 
end  could  be  accomplished  by  placing  the  gagger  against 
the  bar  at  right  angles  and  have  the  heel  parallel  to  the 
face  of  the  slope.  At  C  the  heel  comes  onto  the  slope 
rightly,  but  the  length  of  the  gagger  does  not  come 
against  a  bar,  therefore  it  does  not  hold  anything.  In 
almost  every  case  the  gagger  would  drop  down  when  the 
cope  is  lifted  off.  At  D  the  gagger  is  placed  at  a  slight 
slope  to  the  bar  and  its  heel  parallel  with  the  parting. 
This  will  usually  hold  quite  well,  but  is  not  strong  nor 
a  good  way  to  set  the  gagger.  The  holding  power  de~ 


22  FOUNDRY   PRACTICE 

pends  upon  the  sand  pressing  the  gagger  against  the  bar 
firmly  and  compressing  closely  around  it.  Another  mis- 
take sometimes  made  in  setting  gaggers  is  to  have  several 
located  in  a  corner  against  one  another  and  the  heels 
radiating  in  different  directions  to  hold  in  a  difficult 
place.  The  sand  can  not  compress  around  all  the  gaggers 
or  hold  them  firmly  together.  Part  of  them  are  held 
only  by  the  friction  of  one  on  the  other,  which  is  in- 
sufficient, and  will  drop  out. 

The  number  of  gaggers  needed  is  dependent  upon 
the  sand  used  and  the  width  and  depth  of  the  body 
of  sand  lifted.  When  holding  a  corner  or  edge  of  sand 
by  a  gagger,  have  the  gagger  as  near  as  possible  to  the 
edge  and  parallel  with  it.  Always  be  sure  the  gagger 
is  covered  with  at  least  a  thin  coating  of  sand.  If  not, 
the  iron  is  liable  to  cause  an  explosion  when  coming 
in  contact  with  the  wet  rust.  Before  setting  in  the 
sand,  the  heel  of  the  gagger  must  be  wet  in  clay  wash 
or  flour  paste.  '  Otherwise  the  sand  will  not  stick  to  it. 
Have  at  least  two-thirds  of  the  length  of  the  gagger 
come  against  the  bar,  and  have  the  gagger  as  long  as 
the  cope  will  allow. 

Soldiers  are  wooden  strips  or  pieces  placed  in  the 
sand  to  anchor  the  body  together.  They  are  made  of 
size,  length,  and  shape  to  suit  the  case  where  it  is  to 
be  used.  Oftentimes  soldiers  are  placed  beside  bars 
to  hold  hanging  bodies  of  sand,  instead  of  having  special 
bars. 

The  holding  power  of  soldiers  is  much  greater  than 
that  of  rods  or  nails  as  the  sand  packs  against  their  un- 
even surface  and  will  not  give  without  tearing  up  the 
entire  body  of  sand.  This  will  be  fully  appreciated  if 
you  try  to  pull  a  soldier  out  after  it  is  rammed  into  the 


FOUNDRY  PRACTICE  23 

sand.  The  customary  use  is  for  holding  small  bodies  of 
sand  that  can  not  be  held  by  gaggers.  It  is  not  neces- 
sary to  have  the  soldier  come  against  a  bar.  It  holds 
firmly  when  in  the  body  of  the  sand  itself. 

In  setting  soldiers,  they  should  have  the  lower  end 
wet  in  clay  wash  and  pressed  down  to  place  in  the  sand 
before  ramming.  The  sand  should  be  in  a  loose  coat- 
ing of  about  one  inch  over  the  parting  to  be  soldiered, 
then  when  the  soldier  is  placed,  some  sand  will  remain 
below  the  wood,  but  there  should  not  be  a  thick  coating 
that  may  fall  away  after  the  pattern  is  removed.  The 
main  precaution  is  to  be  sure  that  the  wood  is  covered  by 
sand  and  not  have  that  coating  such  that  it  may  fall 
away  and  expose  the  soldier.  In  case  the  soldier  is 
exposed  to  the  mold,  tlie  molten  metal  will  ignite  the 
wood,  giving  gases  that  can  not  escape  fast  enough,  thus 
causing  the  metal  to  blow.  This  sometimes  throws  the 
metal  for  a  great  distance,  endangering  the  safety  of 
the  men  near  by.  Even  a  very  thin  coat  of  sand  will 
prevent  the  blowing  from  the  soldier. 

The  points  or  corners  of  a  mold  are  usually  held  by 
nails  or  rods.  When  the  body  of  sand  comes  under  the 
pattern,  the  nails  or  rods  are  set  similarly  to  soldiers  and 
rammed  into  the  sand.  When  the  pattern  is  liable  to 
tear  in  drawing  or  a  body  of  sand  is  not  strong  in  itself, 
it  should  be  well  nailed  when  being  rammed. 

Green  sand  cores  which'  are  exposed  at  the  parting 
may  best  be  nailed  after  the  flask  is  rammed,  for  then 
the  nail  head  supports  the  surface  of  the  sand  while 
the  nail  strengthens  the  entire  bod\  of  the  core.  When- 
ever there  is  doubl  of  the  strength  of  a  corner  or  core, 
be  sure  to  secure  well  by  nails. 

Where   the   mold   is   of   such   shape   as   to   endanger 


24  FOUNDRY  PRACTICE 

the  metal  cutting  at  any  point,  the  part  should  be  well 
nailed  after  the '  pattern  is  removed,  leaving  the  heads 
of  the  nails  exposed.  A  few  nails  placed  where  a  cor- 
ner or  surface  is  liable  to  cut  or  wash  by  the  inflowing 
metal  will  prevent  the  washing  away  of  the  sand  and  will 
secure  the  surface  in  a  surprising-  degree. 

Rods  are  often  rammed  in  the  sand  to  strengthen 
and  bind  a  body  of  sand  that  must  resist  a  pressure 
from  the  metal.  Any  large  green  sand  core  must  be 
well  rodded  to  give  the  mass  strength  and  firmness. 
When  the  surface  of  a  green  sand  mold  must  resist 
strong  pressure  of  the  metal,  the  sand  must  be  well 
tied  together  with  rods.  In  a  pit  mold  for  fly  wheels,  the 
head  in  the  risers  gives  a  head  on  the  sand  of  from 
2  ft.  to  4  ft.,  which  means  a  pressure  per  sq.  in.  of  from 
8  to  14  pounds.  This  is  resisted  by  rods  laid  close  to- 
gether in  the  sand  when  the  mold  is  rammed.  In  pockets 
having  metal  under  a  portion  of  them,  giving  a  strong 
lifting  pressure,  rods  are  laid  in  to  take  up  the  strain 
and  secure  the  pocket  firmly. 

A  molcler's  skill  is  shown  in  his  ability  to  patch 
a  mold,  much  more  than  in  any  other  part  of  his  trade. 
In  some  cases  patching  and  botching  are  synonymous, 
but  with  a  good  molder  the  latter  is  not  known.  Many 
patterns  cannot  be  removed  from  the  sand  without  more 
or  less  tearing  of  the  mold,  and  many  old  patterns  are 
used  that  an  unskilled  man  would  think  it  impossible  to 
get  a  good  casting  from.  A  good  molder  will  be  able 
to  repair  a  mold  that  seems  almost  completely  ruined 
when  the  pattern  is  removed,  and  to  get  as  good  a  cast- 
ing as  though  the  pattern  were  perfect  and  he  secured  a 
good  draw ;  the  difference  being  mainly  in  the  time  nee- 
essarv  to  finish  the  mold. 


FOUNDRY   PRACTICE  25 

Practice  and  experience  with  different  cases  and  con- 
ditions can  alone  fit  a  man  to  cope  with  cases  requiring 
much  patching,  but  we  can  offer  a  few  suggestions  that 
may  be  helpful  to  the  beginner.  When  the  sand  is  dry 
or  of  the  proper  temper  for  the  main  body  of  the  mold, 
it  is  nearly  impossible  to  patch  the  sand  at  corners  01 
difficult  places.  To  begin,  then,  the  part  to  be  patched 
should  be  dampened  with  the  swab,  being  careful  not 
to  wet  the  sand  so  as  to  cause  the  casting  to  blow.  In 
patching  a  corner,  place  a  tool  or  a  straight  face  against 
on€  side  and  press  the  sand  in  at  the  other.  A  good 
corner  can  not  be  made  with  a  single  tool  alone.  Sand 
pressed  on  with  the  fingers  may  be  added  to  and  will 
hold  firmly.  When  put  on  with  a  trowel,  a  surface  is 
made  which  will  not  unite  well  with  the  sand  put  on  af- 
terwards. Patching  done  with  the  fingers  will  not  cause 
a  scab  on  the  casting,  but  slicking  a  patch  may  act 
similarly  to  being  rammed  too  hard  at  that  point.  Where 
much  is  to  be  put  on,  put  nails  in  the  place  to  be  patched 
so  the  heads  will  come  a  little  below  the  finished  sur- 
face. The  nails  help  to  hold  the  sand  while  putting  it  on 
and  secure  the  patch  after  it  is  finished.  Whenever 
the  patched  part  is  quite  large,  it  should  be  well  nailed 
after  finishing,  so  that  the  heads  come  flush  with  the 
surface.  In  patching  down  in  a  mold,  sand  may  be  put 
on  by  pressing  small  balls  of  sand  onto  a  tool  so  that  it 
will  carry  its  weight,  then  lowered  to  the  desired  place 
and  lightly  slicked  on. 

In  finishing  the  mold,  the  entire  surface  must  be 
closely  examined  to  be  sure  that  it  conforms  to  the  cast- 
ing desired.  The  loose  sand  at  the  edges  must  be 
pressed  back  to  place  or  removed  so  that  it  will  noi 
fall  into  the  mold  when  the  flask  is  closed,  thus  causing 


26  FOUNDRY  PRACTICE 

a  dirty  casting.  All  loose  sand  in  the  path  of  the  in- 
flowing metal  must  be  removed.  Be  sure  the  runners 
are  so  that  the  sand  will  not  wash  when  pouring  the 
mold. 

The  last  thing  before  closing  a  mold,  a  molder  should 
see  that  all  loose  sand  is  removed  and  the  mold  is  clean. 
If  portions  of  the  mold  are  dark,  light  may  be  thrown 
in  by  a  small  hand  mirror  which  may  be  turned  so  as 
to  light  the  desired  parts. 

Thin  and  weak  patterns  have,  oftentimes,  to  be 
strengthened  by  pieces  which  are  stopped  off  in  the 
mold,  leaving  the  desired  shape  of  casting.  Where  a 
pattern  is  uniform  throughout  its  section  and  casting? 
are  desired  of  different  lengths,  a  pattern  is  made  for 
the  greatest  length  and  the  mold  is  stopped  off  to  the 
desired  length  for  the  casting. 

In  stopping  off  strengthening  pieces,  the  face  of  the 
sand  in  the  part  to  be  filled  is  cut  up  with  a  tool,  then 
filled  with  sand  and  tucked  with  the  fingers.  Fill  in 
small  amounts  at  a  time  so  the  sand  will  be  of  the  same 
hardness  as  other  parts  of  the  mold.  When  within 
about  y2  in.  of  the  finished  surface,  the  part  should  be 
well  vented  through  the  sand.  The  finished  face  is 
slicked  with  the  trowel,  being  careful  not  to  get  the 
face  too  hard. 

When  stopping  off  a  portion  of  the  pattern,  a  stop- 
off  piece  which  conforms  to  the  pattern  at  that  point  is 
laid  in  and  the  end  formed  to  the  piece.  When  without 
a  stop-off  piece,  the  end  is  formed  by  a  trowel  or  a 
piece  of  wood  and  the  sand  filled  in  to  close  that  part  of 
the  mold. 

The  face  of  the  sand  should  :ilways  be  cut  so  the 
sand  pressed  onto  it  will  unite  and  hold  firmlv.  When 


of 
_ 

27 

the  metal  is  not  to  cover  the  face  made  in  the  stopping- 
off,  it  is  not  necessary  to  vent  the  sand  nor  to  be  so 
particular  in  obtaining  an  even  hardness ;  but  it  is  al- 
ways advisable  to  be  as  careful  with  this  as  in  cases 
that  are  more  particular. 

When  a  mold  is  filled,  the  metal  freezes  at  the  sur- 
face first.  The  bottom  solidifies  before  any  other  part, 
then  the  other  surfaces  where  the  heat  is  most  readily 
carried  off.  This  solid  surface  gives  a  fixed  form  which 
resists  any  force  tending  to  change  its  shape.  As  the 
metal  shrinks  upon  solidifying,  something  must  replace 
this  shrinkage.  After  the  outside  surface  is  set,  the  metal 
is  drawn  from  the  still  molten  centre  of  the  casting  to 
replace  the  shrinkage.  This  gives  a  porous,  honey- 
combed, or  rotten  centre  which  has  no  strength.  This 
defective  condition  is  prevented  by  feeding  hot  iron 
to  the  centre  of  the  casting  while  it  is  solidifying  to 
replace  this  shrinkage. 

There  are  two  general  methods  of  feeding  a  casting ; 
first,  using  a  sinking  head ;  second,  feeding  by  use  of 
a  feeding  rod.  A  sinking  head  is  where  the  mold,  when 
standing  in  a  vertical  position,  is  made  longer  than  the 
desired  casting  and  of  the  same  size.  The  excess  length 
is  filled  with  metal  and  allowed  to  sink  to  replace  the 
shrinkage  of  the  casting  below.  This  excess  is  turned 
off,  giving  the  solid  casting.  To  greatly  reduce  the 
work  of  turning  off  a  large  part  of  a  casting,  the  feed- 
ing head  is  made  much  smaller  than  the  casting  arid 
kept  open  by  means  of  a  feeding  rod. 

The  feeding  head  must  always  be  large  enough  to 
enable  it  to  be  kept  open  until  the  casting  below  has  set. 
When  the  feeding  head  is  small,  it  freezes  almost  before 
a  rod  can  be  inserted,  hence  does  not  accomplish  the 


28  FOUNDRY  PRACTICE 

purpose.  It  is  always  safe  to  expect  that  some  of  the 
metal  will  freeze  to  the  sides  of  the  feeder  all  the  time, 
even  if  the  metal  is  kept  in  motion  constantly;  hence 
the  feeder  must  be  increased  to  allow  for  this  in  pro- 
portion to  the  time  that  it  should  be  kept  open.  A  feed- 
ing rod  can  not  be  used  to  advantage  in  a  feeder  less  than 
3  in.  in  diameter.  Th'is  can  be  kept  open  only  a  short 
time,  hence  becomes  ineffective  where  the  casting  be- 
low requires  quite  a  time  to  solidify.  Where  a  large 
feeder  can  not  be  used,  due  to  bars  or  to  conditions  that 
can  not  be  avoided,  a  small  one  may  be  made  to  keep 
open  longer  by  increasing  its  length  and  supplying  hot 
iron  to  heat  this  portion  above  that  of  the  casting. 

A  large  riser  or  feeder  may  have  a  much  smaller 
opening  into  the  casting  and  still  be  as  effective.  A 
3-in.  feeder  may  have  an  opening  into  the  casting  I1/ 
in.  in  diameter  and  give  as  good  results  as  though  the 
full  size  of  the  feeder  were  opened  through.  This 
allows  the  use  of  a  much  larger  feeder  and  still  its  re- 
moval from  the  casting  as  easily  as  the  smaller  one.  The 
smaller  opening  is  kept  from  freezing  by  use  of  the 
feeding  rod. 

The  rod  should  be  heated  in  the  ladle  before  lowering 
into  the  feeder,  to  prevent  chilling  the  iron.  It  should 
be  lowered  slowly  into  the  mold  until  the  bottom  is 
touched,  then  lifted  2  or  3  inches  and  given  an  up 
and  down  motion.  Due  to  this  motion  it  is  commonly 
called  "pumping,"  or  "churning,"  a  casting.  The  feed 
rod  should  not  strike  the  bottom  of  the  mold,  as  it  is 
liable  to  punch  a  hole  in  the  mold,  causing  a  bunch  on 
the  casting.  The  rod  should  be  held  at  one  side  of 
the  centre  and  moved  around  to  keep  as  large  ?n  open- 
ing as  possible  at  the  entrance  of  the  feeder  into  the 


FOUNDRY  PRACTICE  29 

casting.  A  casting  properly  fed  will  freeze  from  the 
bottom  and  slowly  crowd  the  feed  rod  out  of  the  casting 
until  at  last  it  is  only  in  the  riser. 

The  job  of  feeding  a  casting  is  not  a  pleasant  one. 
The  direct  radiation  from  the  metal  and  the  burning 
gases  about  the  flask  make  it  very  hot  and  disagreeable 
work.  For  this  reason,  many  molders  will  freeze  up  a 
riser  long  before  the  casting  below  has  set.  It  is  very 
marked  that  often  in  feeding  a  number  of  the  same  cast- 
ings, poured  at  the  same  time,  part  of  the  men  will 
have  their  feeders  frozen  long  before  the  others  do. 
Those  who  froze  theirs  first  have  castings  the  same  on 
the  surface  as  the  others,  but  the  centres  would  be  very 
different  were  the  castings  cut  open.  The  man  keeping 
his  feeder  open  the  longe'st  has  the  strongest  and  most 
solid  casting. 

The  size  of  the  rod  used  is  unimportant  except  when 
it  is  so  large  that  it  closes  up  the  feeder  rather  than 
keeping  it  open.  In  a  feeder  smaller  than  3  in.,  the 
feeding  rod  should  be  ^4-in.  For  larger  feeders,  the  rod 
may  be  increased.  A  %-in.  rod  is  most  commonly  used, 
as  larger  ones  become  too  heavy  to  handle  without  quick- 
ly tiring  the  workman. 

The  proper  setting  and  venting  of  cores  is  an  im- 
portant factor  in  molding.  Cores  are  made  of  sand  with 
binders  which,  when  dry,  form  a  solid  mass  of  the  desired 
shape.  They  are  placed  in  a  mold  to  make  the  casting 
different,  in  part,  from  the  pattern.  When  burned  by 
the  molten  metal,  the  core  crumbles  and  leaves  the 
casting  hollow  in  that  part.  The  core  may  be  made 
to  form  recesses  in  the  casting,  or  holes  of  desired  shape 
through  the  casting,  or  to  hollow  out  the  inside  of  the 
casting. 


30  FOUNDRY   PRACTICE 

The  binders  which  hold  the  sand  together  in  the  core, 
the  entrained  gases  of  the  new  sand,  and  other  con- 
stituents of  the  core  burn  out  forming  a  volume  of  gas 
that  must  be  allowed  to  escape  when  the  metal  comes 
in  contact  with  the  core.  If  the  gases  are  not  properly 
carried  off,  they  force  their  way  through  the  easiest 
relief,  which  may  be  through  the  molten  metal,  causing 
blowing;  this  spoils  the  casting,  making  the  body 
spongy,  if  not  blowing  nearly  all  the  metal  out  of  that 
portion  of  the  mold. 

When  a  core  is  made,  vents  are  always  provided  to 
carry  the  gases  to  some  particular  points  where  they 
may  be  conducted  away  through  the  sand  of  the  mold. 
A  core  completely  surrounded  with  metal,  except  at 
its  vent,  must  be  well  provided  with  free  passage  for 
the  gases.  Cores  having  the  metal  only  on  one  face,  as 
slab  cores  covering  a  plane  surface,  do  not  require 
special  venting,  as  the  sand  will  carry  off  the  gases 
freely  enough.  Small  cores  partly  surrounded  with 
metal  do<  not  require  special  venting,  as  the  sand  will 
be  sufficient  to  take  up  the  small  amount  o'f  gases  given 
off. 

Where  prints  are  provided  on  the  pattern  for  simple 
cores,  the  setting  of  the  core  is  a  simple  matter.  The 
vent  must  be  provided  for,  then  the  core  is  lowered  into 
the  print  recess  which  anchors  the  core  in  the  desired 
position.  Round  cores  having  a  print  at  both  ends 
must  be  set  into  the  drag  so  as  to  enter  the  print  of 
the  cope  without  tearing  up  the  top  of  the  mold.  This 
can  be  done  by  the  eye  in  lining  it  from  different  direc- 
tions, being  sure  that  it  is  directed  vertically.  Horizontal 
cores  have  the  print  of  both  ends  to  rest  the  core  on. 
The  cores  thus  far  considered  are  held  in  position  by 
the  print  recess  in  the  mold. 


FOUNDRY  PRACTICE  31 

Many  forms  of  cores  have  prints  for  locating  the 
core,  but  nothing  to  hold  the  core  from  floating  when 
the  metal  is  poured  into  the  mold.  Small  cores,  as  those 
for  making  a  hole  in  a  depressed  lug,  may  be  anchorel 
by  placing  nails  slantwise  into  the  sand  to  bear  against 
the  core. 

Large  cores  resting  in  the  drag  are  held  down  by 
means  of  chaplets,  as  considered  under  the  setting  of 
chaplets,  pages  34-36. 

Many  cores  have  no  print  in  the  drag  but  have  one 
in  the  cope.  In  such  cases  the  cores  are  anchored  in 
the  cope  by  wires  so  as  to  hold  their  weight  before  the 
mold  is  poured;  then  when  the  metal  tends  to  float  the 
core,  the  sand  bears  the  stress.  In  green  sand  copes,  the 
core  may  be  anchored  by  running  a  soft  iron  wire  from 
the  loop  in  the  core  to  the  top  of  the  cope,  then  fas- 
tening firmly  to  a  cross  bar  or  to  a  rod  resting  on  the 
cope  bars.  In  dry  sand  copes  having  heavy  cores, 
the  cores"  are  often  bolted  to  cross  beams  by  bolts  hav- 
ing a  hook  to  enter  the  loop  in  the  core. 

Cores  are  sometimes  of  such  form  or  weight  as  to 
require  straps  for  lowering  them  into  the  mold.  Heavy 
core's  may  be  set  by  a  crane,  when  straps  are  used,  which 
bend  easily  to  prevent  tearing  the  sand  when  being  re- 
moved from  the  mold. 

Chaplets  are  used  for  anchoring  cores  into  a  mold 
when  the  cores  are  of  such  shape  that  they  are  not  prop- 
erly supported  by  the  sand.  The  forms  and  types  of 
these  chaplets  vary  greatly.  The  two  main  types  are  the 
single-headed  and  the  double-headed  chaplets,  as  shown 
in  Fig.  5.  The  simple  form  of  single-headed  chaplet 
is  shown  at  a.  This  has  the  forged  head,  having  burrs  at 
N  to  secure  the  chaplet  more  firmly  in  the  metal.  The 


FOUNDRY  PRACTICE 


O 


Fig.  5. 


FOUNDRY  PRACTICE  33 

end  may  be  sharp  or  blunt,  to  suit  the  place  where  it 
is  to  be  used,  b  shows  a  stem  on  which  a  head  of  de- 
sired size  and  shape  may  be  riveted,  d  shows  the  double- 
end  forged  chaplet.  These  are  made  of  any  desired 
length  between  outside  faces  varying  by  1/16  of  an  inch. 
c  is  a  stem  for  a  double-headed  chaplet.  Any  size  or 
form  of  head  may  be  riveted  on  to  suit  particular  cases. 
e  shows  a  double-end  chaplet  and  nail.  The  nail  holds 
the  chaplet  in  position  before  the  core  rests  on  it.  This 
assists  in  setting  in  some  cases.  The  one  shown  has 
riveted  heads  making  use  of  a  stem  on  which  the  de- 
sired heads  are  placed.  /  gives  a  form  of  chaplet  made 
of  cast  iron.  This  is  a  cheap  double-end  chaplet  which 
may  be  made  where  it  is  used,  g  shows  an  adjustable 
double-end  chaplet.  It  is  threaded  into  both  heads  with 
the  stem  threaded  to  allow  the  adjustment.  The  chap- 
let  and  stand  are  shown  at  h.  This  enables  quick  ad- 
justment of  chaplets,  as  the  stand  is  rammed  in  the  drag 
against  the  pattern;  hence  the  chaplet  may  be  dropped 
into  place  when  the  pattern  is  removed.  A  form  of 
spring  chaplet  shown  at  i  may  be  used  to  substitute  for 
a  double-headed  chaplet  and  springs  to  give  the  desired 
distance  between  faces. 

The  most  common  forms  of  chaplets  are  those  shown 
at  a,  b,  c,  and  d.  There  are  firms  making  these  of  all 
sizes  and  shapes.  They  may  be  purchased  at  a  lower 
cost  than  they  could  be  made  without  the  use  of  special 
machinery. 

In  using  chaplets,  a  few  precautions  should  be  ob- 
served. Chaplets  placed  in  a  mold  weaken  the  resulting 
casting  in  a  greater  or  less  degree.  It  is  always  prefer- 
able to  avoid  their  use  where  possible.  They  weaken  the 
casting :  first,  by  introducing  a  foreign  metal  into  casting, 


34  FOUNDRY  PRACTICE 

thus  destroying  the  uniformity  of  the  metal;  second,  by 
forming  blow-holes  or  porous  metal  about  chaplet;  and 
third,  by  failing  to  unite  with  the  metal,  thus  becoming 
loose  or  leaving  a  hole  in  the  casting.  These  evils  may 
be  greatly  reduced  by  proper  design  and  use.  The  first 
cannot  be  avoided,  but  may  be  made  small  by  using  chap- 
lets  of  proper  size  and  shape  to  cause  the  least  possible 
break  in  the  uniformity  of  the  metal.  The  second  may 
be  nearly  always  avoided  by  proper  care  in  regard  to  the 
condition  of  the  surface  of  the  chaplet.  Moisture  on  the 
chaplet  holds  the  metal  away,  causing  blow-holes.  Rust 
makes  the  metal  boil  and  blow,  causing  porous  metal  to 
form.  The  coating  on  the  chaplet  must  be  such  that  the 
iron  will  unite  with  it  and  lie  quiet.  Red  lead  put  on 
with  benzine  makes  a  good  coating.  A  tinned  surface 
gives  the  best  satisfaction  for  this  purpose. 

The  third  evil  may  be  avoided  by  so  shaping  the 
chaplet  that  the  metal  will  adhere  closely  and  bind  itself 
to  the  chaplet.  This  may  be  done  by  having  notches  or 
depressions  in  the  stem  as  shown  at  e,  Fig.  5,  or  by  barbs 
or  burrs,  as  N  on  a.  In  some  cases  the  thickness  of  the 
metal  where  the  chaplet  is  placed  is  not  sufficient  to  en- 
sure a  firm  hold  on  the  chaplet.  The  thickness  should 
be  increased  around  the  chaplet  by  cutting  away  the  sand, 
forming  a  button  having  the  chaplet  in  its  centre. 

The  effective  strength  or  holding  power  of  a  chaplet 
is  dependent  upon  the  way  it  is  set  in  the  mold  and  the 
manner  of  wedging  it  after  the  flask  is  clamped.  Many 
castings  are  lost,  due  to  improper  setting  of  the  chaplets. 
The  chaplet  must  have  a  firm  bearing  on  the  core  and 
the  pressure  it  is  to  resist  must  act  directly  against  its 
length.  When  so  placed  that  the  pressure  tends  to  move 


FOUNDRY  PRACTICE 


35 


it  sidewise,  the  resisting  power  is  only  that  of  the  sand 
around  the  chaplet. 

The  chaplets  set  in  the  drag  must  come  to  a  bearing 
where  it  is  to  remain.  Those  in  the  cope  extend  through 
and  are  held  against  the  core  by  wedges  or  weights  from 
above.  Where  the  flask  has  a  bottom  board,  the  chaplets 
set  in  the  drag  may  be  pointed  and  driven  into  the  bot- 


Fig.  6. 

torn  board  as  shown  at  a  and  d.  Fig  6.  The  head  of  the 
chaplet  should  conform  to  the  shape  of  the  core.  If  the 
head  is  not  shaped  the  same  as  the  core  at  the  point  of 
bearing,  the  chaplet  may  cut  into  the  core,  thus  not  hold- 
ing it  in  the  proper  position,  or  the  bearing  may  be  on 
one  side  of  the  chaplet,  which  may  tip  it  over.  Where 
the  sand  is  very  deep  below  the  point  where  the  chaplet  is 


36  FOUNDRY  PRACTICE 

to  be  placed,  or  there  is  no  bottom  board  to  drive  the 
chaplet  into,  a  block  may  be  rammed  into  the  sand  as  at 
the  base  of  c.  The  chaplet  must  be  set  vertical,  for,  if 
slanting,  the  effect  will  be  that  shown  at  c.  This  chaplet 
has  bearing  only  at  the  edge  and  will  hold  but  little,  as 
the  sand  will  crush  beside  the  chaplet,  allowing  the  core 
to  move.  Where  many  chaplets  of  the  same  length  art 
to  be  set,  as  in  duplicate  work,  much  time  may  be  saved 
by  ramming  in  the  mold  the  chaplet  stand  shown  at  b. 
When  the  pattern  is  removed,  the  chaplet  may  be  placed 
in  the  stand,  thus  saving  the  adjustment  of  height  and 
driving  to  a  firm  bearing  as  required  in  previous  cases. 
There  are  many  other  conditions  to  be  considered  in 
setting  chaplets  in  the  cope.  It  is  best  to  pass  a  vent 
wire  through  the  cope  at  the  point  where  the  chaplet  is 
to  be  placed,  then  gradually  increase  the  size  of  the  rod 
until  nearly  the  size  of  the  chaplet,  when  it  may  bt 
pressed  through  the  sand.  By  thus  slowly  increasing 
the  size  of  the  hole,  the  sand  is  compressed  and  not 
cracked  or  loosened,  as  may  be  done  when  too  great  a 
pressure  is  exerted  in  inserting  a  large  rod  or  chaplet. 
The  chaplet  should  be  drawn  out  when  first  inserted  and 
the  hole  reamed  as  shown  at  o.  This  avoids  the  danger 
of  the  chaplet  pulling  down  the  sand  around  it,  as  at  g, 
when  the  chaplet  is  brought  to  a  better  bearing  or 
wedged  down  after  closing  the  cope.  Where  the  chaplet 
bears  on  the  slant  side  of  a  core,  the  head  should  be  bent 
at  the  same  angle  as  that  of  the  core,  as  at  if  to  ensure  a 
firm  bearing.  Where  the  exact  shape  of  the  core  is  not 
important,  a  level  place  may  be  filed  into  the  core,  thus 
allowing  the  use  of  a  chaplet  having  the  head  at  right 
angles  to  the  stem.  The  chaplet  must  not  be  placed  as 
shown  at  h,  Fig.  6,  for  it  is  liable  to  slide  down  the  slope, 


FOUNDRY  PRACTICE  37 

thus  tending  to  displace  the  core  or  to  crush  the  sand 
around  the  stem  of  the  chaplet. 

Chaplets  may  be  properly  set  in  the  mold  and  ar- 
ranged so  as  to  give  the  best  service  possible,  but  still  be 
rendered  ineffective  by  improper  wedging.  The  pres- 
sure resisted  by  chaplets  may  oftentimes  be  very  great, 
especially  in  large  ones.  The  wedges  must  be  so  placed 
that  the  pressure  may  be  held  without  any  tendency  to 
move  the  chaplet  sidewise.  This  cannot  be  done  with 
one  wedge,  as  that  gives  the  bearing  of  the  stem  onto 
the  slant  surface.  The  double  wedge,  as  at  m,  gives  a 
firm  bearing  on  a  surface  at  right  angles  to  the  stem  of 
the  chaplet.  The  taper  of  the  wedges  should  be  very 
small  so  as  to  avoid  slipping  when  the  pressure  is  exerted 
on  them.  Many  times  the  chaplet  is  too  short  for  using 
wedges  alone ;  then  a  block  must  be  inserted.  This  is  as 
good  as  the  wedges  alone  when  the  surfaces  of  the  block 
and  the  wedges  are  kept  at  right  angles  to  the  chaplet. 
Some  of  the  incorrect  methods  of  wedging  with  a  block 
are  shown  at  n,  r,  and  s.  At  n,  the  single  wedge  has  been 
driven  from  one  side,  thus  tilting  the  chaplet  so  it  is 
liable  to  move  over  when  the  pressure  acts  against  it 
The  single  wedge  effect  is  also  shown  at  s.  It  is  a  poor 
plan  to  insert  wedges  from  opposite  sides  of  a  block  not 
bearing  on  each  other,  as  at  r  and  n.  The  block  is  quite 
liable  to  be  tilted  or  the  wedges  to  loosen  at  one  side, 
causing  damage. 

Another  improper  use  of  wedges  is  shown  at  t.  Here 
the  wedges  are  either  of  different  tapers,  or  so  placed 
that  the  one  resting  on  the  chaplet  has  a  bearing  only  at 
the  ends.  This  may  give,  or  the  wedge  break  when  the 
pressure  is  applied.  Cast  iron  wedges  placed  in  this 


38  FOUNDRY  PRACTICE 

manner  on  heavy  work  have  been  broken,  thus  allowing 
the  core  to  rise. 

Wedges  made  of  hard  wood  give  good  satisfaction  in 
light  work.  Wrought  and  cast  iron  wedges  are  more  re- 
liable and  may  be  used  in  any  case. 

The  parts  of  a  mold  are  held  together  by  properly 
clamping  or  weighting  the  cope  and  cores  before  cast- 
ing. The  stress  upon  the  cope  due  to  the  molten  metal 
when  a  flask  is  poured  is  dependent  upon  many  con- 
ditions. The  main  force  is  that  of  the  static  fluid  while 
the  metal  is  still  a  liquid.  A  second  force  that  in  some 
cases  is  of  great  magnitude  is  that  due  to  the  momen- 
tum of  the  metal  when  the  mold  fills  and  the  metal 
comes  up  in  the  riser.  This  force  may  be  inappreciable 
in  many  cases.  In  particular  cases  there  appears  to  be 
a  force  exerted  that  can  not  be  well  accounted  for,  but 
which  must  be  provided  against  when  liable  to  appear. 

The  static,  or  fluid,  pressure  on  a  cope  may  be  cal- 
culated directly.  Before  giving  the  method  of  determin- 
ing the  force,  let  us  understand  what  causes  this  force. 
The  metal  when  molten  is  a  fluid  the  same  as  .water,  and 
it  passes  from  the  fluid  state  to  the  solid  when  the  tem- 
perature lowers  below  its  fusion  point,  the  same  as  water 
becomes  ice  as  soon  as  it  cools  below  32°  F.  or  o°  C.  The 
same  laws  hold  true  with  each  fluid  while  in  the  same 
state  of  fluidity.  Since  water  is  better  known,  let  us  con- 
sider that  we  are  handling  water ;  then  by  the  change  of 
weight  we  will  have  the  conditions  existing  in  the  case 
of  molten  iron.  Any  body  lighter  than  water  will  sink 
into  its  surface  until  it  has  displaced  an  amount  equal  to 
its  own  weight.  In  order  to  press  the  body  further  into 
the  water  a  force  must  be  exerted  equal  to  the  weight  of 
the  water  displaced.  When  once  the  body  becomes  im- 


FOUNDRY  PRACTICE  39 

mersed,  only  a  slight  increase  of  the  force  will  sink  it  to 
any  depth.  This  additional  pressure  is  small  enough  so 
it  may  be  neglected  in  cases  that  we .  consider.  This 
gives  the  action  that  takes  place  upon  a  core  that  is  sur- 
rounded by  metal.  The  pressure  exerted  upon  any  sur- 
face by  the  water  is  due  to  the  area  of  the  surface  and 
the  height  of  the  water  above  that  surface.  In  fluids  the 
pressure  at  any  point  is  equal  in  all  directions  and  is 
transmitted  without  loss  throughout  its  entire  body.  Thus 
if  a  tank  be  tight  and  have  a  small  pipe  extending  direct- 
ly above  it,  and  it  be  filled  with  water  until  the  pipe  is 
partly  filled,  the  pressure  on  any  cross-section  is  the  same 
as  though  the  tank  extended  at  its  maximum  size  and 
were  filled  to  the  same  level  as  that  in  the  pipe. 

The  amount  of  force  necessary  to  hold  down  a  core 
that  is  surrounded  with  iron  may  be  found,  since  it  will 
equal  the  difference  between  its  weight  and  that  of  an 
equal  volume  of  iron.  Sand  weighs  about  .06  Ibs.  per 
cu.  in.,  and  iron  weighs  .26  Ibs.  The  difference  between 
the  two  is  therefore  .2  Ibs.  per  cu.  in.  By  rinding  the 
volume  of  the  core  in  cubic  inches  and  multiplying  .2 
Ibs.  by  this  number  we  have  the  weight  necessary  to  hold 
the  core  down  when  the  mold  is  poured.  If  the  core 
has  metal  partly  around  it,  the  pressure  will  be  the  same 
as  that  exerted  on  the  sides  of  the  mold  at  that  level. 

The  pressure  exerted  on  the  cope  will  be  that  due  to 
the  head  above  the  surface  of  the  cope  and  acting  on 
the  area  of  mold  which  the  cope  covers.  This  can  be 
more  plainly  understood  by  taking  a  particular  case,  as 
a  plate  whose  top  is  12  in.  by  24  in.,  and  having  a  cope 
16  in.  by  24  in.  and  6  in.  deep.  The  head  on  the  face  of 
the  cope  will  then  be  .6  in.  The  area  of  the  mold  is  I2x 
24,  or  288  sq.  in.  The  volume  of  metal  which  would  be 


40  FOUNDRY  PRACTICE 

equivalent  to  the  pressure  is  288x6,  or  1,728  cu.  in.  Its 
weight  will  be  i,728x.26,  or  499.28  Ibs.  The  weight  of 
the  cope  will  be  its  volume  in  cu.  in.  x  .06,  the  weight 
of  a  cu.  in.  of  sand,  or  26xi6x6x.o6  —  113.76  Ibs.  There- 
fore the  additional  weight  required  upon  the  cope  will 
be  449.28—113.76  =  335.52  Ibs. 

The  magnitude  of  the  force  due  to  momentum  can 
not  be  calculated  and  is  dependent  upon  the  style  of  gate 
and  rapidity  of  pouring.  If  the  mold  is  poured  slowly, 
the  metal  rises  slowly  and  comes  up  in  the  riser  easily, 
exerting  no  force  of  momentum.  If,  on  the  other  hand, 
the  metal  is  poured  in  rapidly,  and  the  mold  fills  quickly, 
the  moment  of  the  flowing  metal  lias  to  be  overcome  by 
the  cope,  which  stops  its  flow  suddenly. 

The  style  of  gate  has  a  great  influence  upon  the 
amount  of  the  pressure  due  to  momentum.  If  the  metal 
is  poured  into  a  basin,  the  fall  of  the  metal  from  the  ladle 
is  broken  and  the  iron  enters  the  gate  with  but  little 
force.  Therefore  the  pressure  in  the  mold  will  be  prac- 
tically that  due  to  a  head  the  height  of  the  surface  of  the 
metal  in  the  basin.  When  the  metal  is  poured  directly 
into  the  gate,  a  much  greater  momentum  is  attained 
The  metal  falling  from  the  ladle  into  the  gate  attains  a 
velocity  and  consequent  energy  which  is  exerted  upon 
the  metal  in  the  gate.  This  gives  a  pressure  almost  equiv- 
alent to  that  produced  by  a  head  the  height  from  which 
the  metal  falls.  The  allowance  necessary  to  cover  thi? 
extra  force  makes  the  safe  weight  one-half  larger  than 
that  calculated  for  the  statical  head.  This  will  take  care 
of  all  other  force  not  accounted  for. 

Castings  are  often  lost  by  putting  too  great  a  weight 
upon  the  cope  or  by  drawing  the  clamps  too  tight,  thus 
causing  a  crush  in  the  mold. 


FOUNDRY  PRACTICE  41 

In  clamping  a  cope,  the  main  idea  is  to  hold  the  flask 
firmly  together  so  it  can  not  strain  at  any  point  allowing 
the  metal  to  run  out.  It  is  not  necessary  to  put  great 
pressure  on  the  cope  with  the  clamps  in  order  to 
hold  the  metal.  After  the  clamp  is  tight  so  it  can  not 
give,  any  additional  pressure  on  the  clamp  is  more  detri- 
mental than  beneficial.  The  clamp  should  be  stood  near- 
ly straight  and  tightened  onto  the  wedge  with  a  clamp- 
ing iron,  as  shown  in  Fig.  21.  Clamps  should  be  placed 
near  enough  together  to  avoid  straining  the  flask  between 
them. 

The  strength  of  a  clamp  throughout  its  central  part 
where  the  stress  is  tense  may  be  calculated,  allowing  5,- 
ooo  Ibs.  per  sq.  in.  of  cross-section  for  cast  iron  and  15,- 
ooo  Ibs  per  sq.  in.  for  wrought  iron.  The  greatest  stress 
on  the  clamp  is  at  the  corner  and  that  is  dependent  upon 
the  leverage  to  the  bearing  point.  The  corner  must  be 
greatly  reinforced  to  make  it  equal  to  the  other  part. 
Wrought  iron  clamps  are  usually  made  by  bending  a  bar, 
which  makes  them  weaker.  The  force  they  will  resist  is 
that  necessary  to  bend  the  corner. 

T.he  volume  of  a  given  weight  of  iron  changes  as  it 
passes  from  the  liquid  to  the  solid  state.  This  diminution 
of  volume  upon  solidification  is  called  shrinkage.  The 
amount  of  shrinkage  varies  with  the  chemical  composi- 
tion of  the  iron.  The  average  shrinkage  is  an  eighth  inch 
to  one  foot  in  length.  This  shrinkage  is  allowed  for  in 
the  patterns  by  use  of  the  pattern  scale  whose  dimensions 
are  that  amount  in  excess  of  the  standard  scales.  The 
volume  also  reduces  after  solidification  as  the  tempera- 
ture reduces  to  that  of  the  atmosphere.  This  is  often 
treated  as  the  contraction  of  the  iron,  but  it  is  more  sim- 
ple to  combine  the  two  and  treat  it  as  shrinkage.  The 


42  FOUNDRY  PRACTICE 

feeding  of  large  casting  is  for  the  purpose  of  supplying 
metal  to  the  interior  of  the  casting  to  replace  that  drawn 
away  by  the  shrinkage  after  the  outer  shell  has  become 
set. 

Many  castings  are  lost  due  to  holes  in  the  casting 
where  it  should  be  solid  and  filled  to  the  form  o>f  trie  pat- 
tern. These  holes  may  be  from  either  or  both  of  two 
causes :  first,  the  casting  may  blow,  or,  second,  the  shrink- 
age draws  away  the  metal  from  a  particular  point.  The 
defects  are  called  blow-holes  in  the  first  case  and  shrink- 
holes  in  the  second.  The  causes  of  the  first,  or  blow- 
holes, may  be  various.  It  is  the  gases  failing  to  escape 
from  the  face  of  the  mold  or  some  core  and  forcing  their 
way  through  the  molten  metal,  leaving  the  opening  when 
the  metal  sets.  A  few  causes  may  be  mentioned  which 
are  most  common :  too  wet  sand,  too  hard  ramming,  im- 
proper venting  of  sand  or  cores,  wood  or  rusty  iron 
coming  in  contact  with  the  molten  metal,  or  faces  such 
that  the  metal  will  not  lie  quietly  against  them.  These 
holes  are  characterized  by  rough,  irregular  surfaces,  and 
have  the  appearance  of  gas  enclosed. 

Shrink-holes  are  caused  by  the  drawing  away  of  the 
metal  to  replace  the  shrinkage  while  solidifying.  These 
are  caused  by  failure  to  supply  feeding  iron  to  the  heavy 
parts  after  the  surface  has  set.  It  may  be  due  to  the  form 
of  the  casting  or  to  insufficient  feeding  when  such  is 
provided.  The  point  where  such  a  shrink-hole  is  most 
liable  to  be  is  where  there  is  a  break  in  the  regular  sur- 
face of  the  casting;  as  under  a  feeding  head  which  was 
of  insufficient  size,  where  the  gate,  or  riser,  is  cut  into 
the  casting,  where  a  lighter  part  of  the  casting  joins  to 
the  heavier  part,  or  at  the  top  surface  when  no  weak 
point  is  adjacent. 


FOUNDRY   PRACTICE  43 

These  holes  are  characterized  by  smooth  holes  de- 
pressed into  the  casting  with  solid  bases,  or  depressions 
in  the  casting  having  the  appearance  of  a  shell  solidify- 
ing in  contact  with  the  face  of  the  mold,  then  drawn 
down  by  the  shrinkage.  When  the  shrink-hole  is  not  at 
the  surface  it  may  take  a  very  different  appearance.  The 
honeycombing  at  the  centre  of  large  castings  is  due  to 
the  shrinkage  drawing  the  metal  away  from  the  centre 
after  the  outer  shell  has  become  of  such  strength  as 
to  resist  the  shrinkage  strains. 

The  remedies  for  such  shrink-holes  are  to  make  feeding 
heads  of  ample  size  and  feed  the  casting  until  the  shrink- 
age is  provided  for,  to  have  the  feeder  connected  to  the 
heaviest  part  of  the  casting,  to  supply  a  feeder  where  the 
shrink-holes  appear,  or,  when  feeding  with  a  rod,  to  keep 
the  feeder  open  until  the  casting  is  set  by  supplying  hot 
iron  in  the  feeding  head. 

Burning  on,  or  casting  on,  is  the  uniting  of  two  parts 
of  a  casting  or  the  forming  of  a  new  part  onto  a  cast- 
ing. It  is  the  welding  of  the  cast  iron  parts.  In  order 
to  form  such  a  weld  the  face  of  the  casting  must  be  heat- 
ed to  a  plastic  or  molten  state.  This  is  accomplished  bv 
pouring  hot  molten  metal  over  the  surface  where  the  weld 
is  to  be  made,  until  it  starts  to  melt  or  becomes  plastic. 

Often  the  arms  of  pulley  castings  break  in  cooling. 
When  the  other  parts  are  sound,  the  arms  may  be  burned 
together,  forming  a  perfect  casting.  This  is  done  by 
chipping  away  the  edges  of  the  break  so  as  to  expose  the 
surfaces  of  the  casting.  The  pulley  is  laid  onto  a  sand 
bed  so  the  top  of  the  arm  is  level.  A  dry  sand  core  is 
fitted  about  the  arm  at  the  bottom  a?td  sides  of  the  break, 
leaving  its  top  entirely  exposed.  A  runner  is  made  to 
lead  the  overflow  away  to  pig  beds.  The  burning  is  ac- 


44  FOUNDRY  PRACTICE 

complished  by  pouring  a  constant  stream  of  metal  onto 
the  break  until  the  surfaces  become  plastic  or  molten. 
The  pouring  is  stopped,  leaving  the  opening  between  the 
cores  filled,  which  unites  the  broken  surfaces 

The  excess  of  metal  is  chipped  off,  giving  the  re- 
paired casting.  The  progress  of  the  burning  can  be  de- 
termined by  scraping  the  face  with  a  rod  while  the  metal 
is  being  poured  onto  it.  When  the  face  of  the  casting 
begins  to  melt  it  can  be  felt  to1  soften  under  the  rod. 
When  the  hard  spots  are  felt,  the  inflowing  metal  should 
be  directed  onto  them  until  the  entire  surface  softens, 
which  marks  the  completion  of  the  process. 

The  method  of  casting  a  piece  onto  a  casting  may  be 
illustrated  by  forming  a  portion  of  the  bracket  onto  the 
column  shown  in  Fig.  55.  Consider  the  bracket  to<  be 
broken  off  along  the  dotted  line  ab.  The  column  is  laid 
on  the  sand  so  the  face  a  is  level.  Dry  sand  cores  are 
fitted  to  enclose  the  bracket,  giving  the  desired  form, 
with  the  top  side  a  open.  A  small  hole  is  left  through 
the  core  at  b.  A  runner  is  led  from  this  hole  to  the  pig 
bed.  The  iron  is  poured  onto  the  broken  surface  at  the 
rate  the  opening  will  allow  it  to  escape.  The  stream  is 
directed  onto  different  points  until  the  entire  surface  be- 
comes plastic.  The  opening  at  b  is  then  closed  with  a 
clay  ball  and  the  bracket  rilled  with  metal,  which  forms 
the  desired  casting. 

Bench  molding  includes  the  light  work  where  the 
mold  is  made  upon  a  bench  and,  after  completion,  the 
mold  is  placed  upon  the  floor  for  casting.  The  bench  is 
so  fitted  that  -the  sandpile  is  under  it  while  shelves  are 
attached  for  holding  the  tools  within  convenient  reach. 
The  bench  is  moved  back  over  the  sand-pile  as  it  is  used, 
while  the  molds  are  placed  in  front  in  a  convenient  ar- 


FOUNDRY  PRACTICE  45 

rangement  for  pouring.  The  molder,  being  in  a  stand- 
ing position,  is  more  comfortable  and  can  produce  more 
molds  than  on  the  floor  in  a  stooping  position. 

The  snap-flask  is  especially  suited  to  this  class  of 
work.  Individual  flasks  of  small  sizes  are  also  used  on 
the  bench.  The  flasks  are  of  such  sizes  that  they  may 
be  handled  easily  from  the  bench  to  floor  after  the  mold 
is  finished.  Ordinarily  the  individual  flask  should  not 
exceed  16  in.  square. 

Bench  molding  is  used  extensively  in  brass  foundries 
The  sand  is  mixed  and  tempered  in  a  box  or  trough  with- 
in convenient  reach  of  the  bench. 

Most  patterns  have  the  lines  of  parting  at  different 
levels  at  different  parts  of  the  pattern.  In  these  cases, 
if  the  pattern  were  laid  on  a  plain  board,  the  molder 
would  be  obliged  to  cut  away  the  sand  to  the  line  of 
parting  of  pattern  and  slick  the  surface  for  the  parting  of 
the  mold.  To  avoid  this  loss  of  time,  a  special  follow- 
board  is  made  which  conforms  to  the  pattern  and  forms 
the  desired  parting  surface  on  the  drag. 

A  match  is  a  follow-board  made  from  new  sand 
rammed  hard,  core  mixtures,  or  any  convenient  material 
that  will  maintain  its  shape  firmly.  A  match  is  often 
made  for  the  present  use  for  a  special  order.  With 
standard  patterns  the  match  is  made  permanent  and  goes 
with  the  pattern.  A  permanent  match  may  be  cheaply 
made  of  core  mixtures.  The  preferable  mixture .  is  that 
of  linseed  oil  and  fine  sand,  because  it  holds  its  shape 
firmly  and  is  not  affected  by  dampness. 

When  there  are  not  enough  castings  to  be  made  from 
a  pattern  to  pay  to  shape  a  special  follow-board,  and  the 
pattern  projects  into  the  cope,  it  is  often  desirable  to 
make  a  match  of  green  sand  in  the  cope  with  the  pattern 


46 


FOUNDRY  PRACTICE 


FOUNDRY  PRACTICE  47 

at  its  proper  location.  The  drag  is  rammed  up  in  its 
position  on  the  cope.  When  turned  over  the  cope  is  re- 
moved, the  sand  is  cleared  away,  and  the  parting  of  the 
drag  is  prepared  for  ramming  the  cope. 

A  plain  board  is  used  as  a  turn-over  or  follow-board 
with  patterns  having  plain  surfaces  or  the  parting  nearlv 
in  the  plane  of  the  face  of  the  drag. 

Molding  machines  are  for  the  purpose  of  expediting 


Fig.  8. 

the  operation  of  molding.  The  term  molding  machine 
does  not  mean  that  the  machine  will  do  the  work  of 
forming  a  mold.  The  molding  machines  may-  be  classi- 
fied under  three  general  heads :  first,  the  machine  for 
mechanically  drawing  the  pattern ;  second,  the  moldinp 
press;  and,  third,  the  machine  with  press  and  mechanical 
drawing  of  the  pattern. 


48 


FOUNDRY  PRACTICE 


FOUNDRY  PRACTICE 


49 


In  the  first  class  of  machine,  the  sand  is  rammed 
by  hand  in  the  usual  manner.  When  ready  to  be  re- 
moved from  the  machine,  the  pattern  is  drawn  down 
by  mechanical  means,  usually  a  lever  or  rack  and  pinion. 


Fig.  10. 


Trie  pattern  is  drawn  through  a  stripping  plate  which 
prevents  the  sand  from  tearing  and  makes  possible  the 
performing  of  the  operation  more  rapidly.  The  hand  is 


;o  FOUNDRY  PRACTICE 

unsteady  and  can  not  hold  the  pattern  so  as  to  move  it 
out  of  the  mold  perpendicular  to  its  face ;  hence,  it  takes 
much  time  and  skill  to  draw  the  pattern  without  tearing  - 
the  mold. 


This  type  of  machine  is  suited  to  a  wide  range  of 
castings.  Many  manufacturers  of  molding  machines  are 
fitted  to  build  a  machine  for  a  very  great  variety  of  pat- 
terns. One  machine  of  this  class  is  shown  in  Fig.  7.  It 


FOUNDRY  PRACTICE  51 

is  for  making  pulleys  of  any  desired  size  and  width  of 
face  up  to  about  44  in.  diameter  with  24  in.  face.  The 
range  for  each  machine  is  about  12  in.  on  the  diameter; 
i.  e.,  a  machine  will  make  all  sizes  from  6  in.  to  18  in. 
in  diameter.  The  changeable  parts  are  the  pattern  ring, 
the  arms,  and  the  stripping  plates  for  each  size  as 
shown  in  Fig.  7.  The  cope  and  drag  are  rammed  on  the 
same  machine,  and  the  pins  are  so  arranged  that  the 
joint  comes  together  correctly  when  the  flask  is  closed. 

The  machine  shown  in  Fig.  8  is  one  of  a  great  variety 
of  machines  which  are  for  a  speciaj  casting,  One  ma- 
chine forms  the  cope  while  the  other  forms  the  drag. 
These  two  machines  are  combined  in  one  for  some  pat- 
terns ;  then  each  flask  contains  two  castings.  Special 
flasks  are  required  for  all  this  type  of  machine. 

The  second  class  of  machine  performs  the  operation 
of  ramming  the  sand  in  the  flask,  while  all  the  other  op- 
erations are  performed  by  hand.  Fig.  9.  represents  a 
press  molding  machine,  or  "squeezer."  The  machine  ful- 
fills the  offices  of  the  bench  used  in  bench  molding,  and 
also  has  the  presser  head  which  compresses  the  sand  into 
the  flask  instead  of  ramming  by  hand.  The  work  hand- 
led on  these  machines  is  the  same  as  that  done  on  the 
bench.  The  snap  flask  is  used  on  all  small  machines. 

Fig.  10  represents  a  press  molding  machine  having 
pneumatic  connections.  The  pattern  is  loosened  by  the 
vibrator  frame  when  the  cope  is  ready  to  be  lifted. 

Fig.  ii  shows  a  multiple  mold  made  by  the  use  of  a 
press  molding  machine  and  the  casting  that  is  obtained 
from  the  mold.  This  secures  the  making  of  a  great  num- 
ber of  molds  on  a  small  floor  space. 

The  third  class  of  moldjng  machine  performs  the  op- 
eration of  ramming  and  drawing  the  pattern.  Fig.  12 
shows  such  a  machine  for  making  ells  as  shown  at  the 


52  FOUNDRY   PRACTICE 

bottom  of  the  figure.  The  presser  head  conforms  to  the 
pattern  leaving  the  cope  as  shown  after  the  sand  has 
been  compressed.  Before  compressing  the  sand  into  the 
flask,  the  sand  frame  is  placed  upon  the  flask  and  filled  to 
its  top.  The  degree  of  hardness  due  to  the  press  is  de- 
pendent upon  the  depth  of  this  sand  frame.  After  strik- 
ing off  and  venting,  the  flask  is  lifted  off  from  the  pat- 


Fig.  12. 

tern  by  the  lift  lever,  thus  mechanically  drawing  the  pat- 
tern.    The  pattern  board  forms  the  stripping  plate. 

These  machines  are  made  for  many  special  patterns 
and  are  claimed  to  give  good  results;  and  they  very 
much  reduce  the  cost  of  making  the  mold. 


CHAPTER  II 


The  method  of  proceeding  in  rr.aking  a  mold  for  a 
plain  casting  may  be  demonstrated  by  consideration  of 
the  pattern  shown  in  Fig.  13.  After  having  the  sand 
properly  tempered,  the  turn-over  board  is  placed  on  a 


V 


\ 


Fig.    13. 


sand  bed  so  as  to  have  bearing  all  over  to  avoid  rocking 
or  unevenness  of  the  top.  The  pattern  is  then  placed 
on  the  board  as  shown  in  Fig.  14.  The  drag  may  now 


54 


FOUNDRY  PRACTICE 


be  placed  over  the  pattern  and  facing  sand  riddled  onto 
the  pattern.  After  the  pattern  is  covered  with  a  light 
coat  of  facing  sand,  heap  sand  is  riddled  to  about  the 
depth  of  6  in.  as  shown  in  Fig.  15. J  The  sand  is 
rammed  around  the  edge  of  the  flask  with  the  pein  ram- 


Fig.  14. 


mer  by  directing  it  as  shown  at  A,  Fig.  15.  It  is  next 
rammed  around  the  pattern  with  the  rammer  directed  as 
shown  at  B,  Fig.  15.  The  sand  falling  between  these 
two  rammings  is  then  rammed  to  an  even  hardness  which 


Fig.  15. 

is  sufficient  to  form  a  firm  body  and  allow  the  free  escape 
of  the  gases. 

Care  should  be  taken  in  ramming,  to  avoid  striking 
he  rammer  nearer  to  the  pattern  than  one  inch.     Wher- 


FOUNDRY  PRACTICE 


55 


Fig.  16. 


ever  the  pein  strikes  the  pattern,  a  hard  spot  in  the  sand 
is  left  which  will  cause  a  scab  on  the  casting.7  The  flask 
is  now  filled  full  of  heap  sand  and  rammed  with  the  butt 


Fig.  17. 


56  FOUNDRY  PRACTICE 

rammer  as  shown  in  Fig.  16.  The  drag  may  now  be 
struck  off  with  a  straight  edge  even  with  its  top,  A  thin 
layer  of  loose  sand  is  then  scattered  over  the  sur- 
face to  ensure  a  good  bearing  on  the  entire  surface  of 
the  bottom  board.  The  drag  should  now  be  vented  with 
one-eighth  in.  wire  all  around  and  over  the  pattern  using 


Fig.  18. 


care  not  to  strike  the  pattern  so  as  to  allow  the  metal  to 
flow  into  the  vent.  The  bottom  board  is  placed  onto  the 
drag,  with  care  that  it  touches  at  all  points.  (  The  two 
boards  are  clamped  to  the  drag  with  short  clamps  as 
shown  in  Fig.  17.  The  flask  is  then  turned  over  onto  a 
bed  of  loose  sand,  so  as  to  have  an  even  bearing  at  both 


FOUNDRY  PRACTICE 


57 


ends.  The  clamps  are  then  removed  and  the  board  taken 
off,  leaving  the  pattern  at  the  top  of  the  drag.  The  joint 
is  made  by  tucking  sand  into  any  soft  places  that  there 
may  be,  then  the  surface  is  slicked  with  the  trowel  by 
leaving  a  little  loose  sand  on  the  surface  so  as  to  make  it 
a  little  harder  than  the  other  parts  of  the  sand.  Parting 
sand  is  dusted  over  the  sand  of  the  joint  until  the  entire 


Fig.  19. 

surface  is  covered.  That  falling  onto  the  pattern  is 
brushed  off.  Since  the  flask  is  small  and  the  cope  has  no 
bars,  it  may  now  be  placed  on  and  the  gate  stick  set  even 
with  the  centre  of  the  pattern  and  midway  between  the 
flask  and  pattern  as  shown  in  Fig.-f8V~(Jhis  pattern  hav- 
ing a  rib  running  lengthwise,  the  inflowing  metal  should 
enter  the  rib  from  an  end  and  not  over  an  edge.  (This 


58  FOUNDRY  PRACTICE 

will  reduce  the  liability  of  the  metal  cutting  away  the 
sand  causing  a  bunch  on  the  casting. )(  A  little  facing 
sand  is  riddled  over  the  pattern,  then  the  heap  sand  is 
riddled  through  a  No.  4  riddle  to  :.i  depth  of  about  one 
inch.  Heap  sand  is  filled  in  and  rammed  next  to  the  flask 
with  the  pein,  then  the  remainder  is  rammed  to  an  even 
hardness.  The  cope  is  filled  and  rammed  with  the  butt 
rammer  and  struck  off  similarly  to  the  drag.  It  is  vented 
over  the  pattern  and  around  the  gate  stick  with  one- 
eighth  inch  vent  wire.  The  gate  stick  is  loosened  by  rap- 
ping sidewise,  then  it  is  withdrawn,  The  hole  is  reamed 
out,  leaving  a/  large  opening  to  pour  the  iron  into,  as 
shown  in  Fjgjj^.  The  cope  is  ready  to  be  lifted  off  and 
placed  on  any  convenient  rest  where  it  may  be  finished. 
The  cope  should  always  be  finished  before  the  drag  is 
touched,  for,  if  anything  happened  to  necessitate  shaking 
it  out,  the  drag  is  ready  to  have  the  cope  replaced  for  an- 
other ramming.  The  portion  of  the  cope  that  covers  the 
pattern  should  be  slicked  lightly  with  the  trowel,  then 
covered  with  plumbago  with  a  soft  camel's  hair  brush,  or 
by  dusting  from  a  sack  and  then  slicking  with  a  trowel. 
The  gate  should  be  reamed  slightly  to  take  off  the  loose 
edge  and  pressed  to  firmness  with  the  fingers.  The  drag 
should  be  brushed  off  to  remove  the  parting  sand ;  then 
wet  the  sand  around  the  pattern  slightly  with  the  swab. 
If  the  sand  is  too  wet  at  any  point  the  metal  will  blow 
when  poured,  therefore  care  must  be  exercised  in  putting 
on  only  as  much  water  as  is  necessary  to  make  the  sand 
stick  together  well.  The  pattern  may  now  be  drawn  by 
driving  the  draw  spike  into  the  centre  of  the  pattern, 
then  rapping  it  until  the  sand  is  free  from  the  edges  of 
the  pattern ;  then  lift  the  pattern  out  by  slowly  raising 
it  as  shown  in  Fig.  20.  The  mold  is  slicked  over  lightly 


FOUNDRY  PRACTICE 


50 


\ 


6o 


FOUNDRY  PRACTICE 


and  patched  in  case  the  pattern  tears  the  sand  at  any 
place.  The  pouring  gate  is  now  connected  to  the  mold 
by  cutting  a  runner  from  the  mold  to  the  gate  of  a  size 


Fig.  21. 


that  will  admit  the  iron  freely,  but  it  must  be  smaller 
than  the  portion  of  the  casting  where  it  connects  so  that 
the  runner  may  be  broken  off  easily  without  damage  to 


FOUNDRY  PRACTICE 


61 


the  casting.  The  runner  should  be  smoothed  with  the 
fingers  or  a  slicking  tool  to  ensure  against  loose  sand 
being  washed  into  the  mold.  The  mold  may  now  be 
dusted  with  plumbago  and  slicked,  at  which  time  the 
flask  is  ready  to  close.  The  flask  should  be  clamped 
to  provide  against  the  cope  being  lifted  by  the  metal 
and  the  metal  flowing  out  at  the  joint  when  the 
mold  is  poured.  In  clamping  a  flask,  it  must  hoi;  be 
moved  or  jarred,  as  the  sand  hanging  at  the  top  is 
liable  to  drop.  Nor  should  the  cope  and  drag  be  drawn 
together  with  •a  great  pressure  as  the  flask  is  liable  to 


Fig.  22. 


give,  causing  the  sand  to  crush  in  the  mold  at  the  joint. 
The  best  method  of  putting  on  the  clamps  is  to  have 
them  stand  nearly  vertical  and  resting  on  a  wedge  at 
the  top.  The  clamp  may  be  tightened  with  a  clamping 
iron  by  catching  the  point  under  the  clamp  and  on  the 
wedge,  then  moving  the  upper  end  toward  the  clamp  as 
indicated  by  the  arrow  in  Fig.  21.  The  mold  is  now 
ready  to  cast. 

The  process  of  making  a  mold  with  a  split,  or  divid- 
ed pattern  is  shown  by  the  small  pulley  in  Fig.  22.  The 
half  of  the  pattern  without  the  dowel-pins  is  placed  on 


62 


FOUNDRY  PRACTICE 


the  turn-over  board  and  the  drag  placed  on  it  as  in  the 
previous  case.  The  facing  sand  is  put  on  until  the  arms 
are  covered,  then  heap  sand  is  riddled  through  a  No.  4 
riddle  until  the  centre  is  rilled  to  the  top  of  the  rim. 


Fig.  23. 

Since  the  hub  is  deeper  than  the  rim,  there  is  liability  of 
the  sand  crushing  out  when  the  mold  is  poured,  as  the 
hub  fills  to  the  height  of  the  arms  before  the  rim  receives 
any  iron.  To  prevent  the  sand  from  breaking  and  to 
hold  it  together  more  firmly,  wooden  soldiers  are  put 


Fig.  24. 

into  the  sand  between  the  rim  and  the  hub.  The  soldiers 
are  made  of  any  small  pieces  of  wood,  only  large  enough 
to  be  stiff  and  of  a  length  to  reach  beyond  the  pattern 
about  the  same  distance  as  it  is  inserted  into  it.  They 
are  wet  with  clay  wash,  or  flour  paste,  to  hold  the  sand  to 


FOUNDRY  PRACTICE  63 

the  soldier.  They  are  placed  to  a  depth  of  the  arms  about 
midway  between  the  rim  and  hub,  and  between  the  arms, 
as  shown  in  Fig.  23. 

The  pattern  is  now  completely  covered  with  riddled 
sand  and  the  outside  rammed  as  before.  The  sand  with- 
in the  pattern  is  rammed  with  any  small  tool  or  stick  that 
can  be  gotten  in  between  the  soldiers  and  the  pattern. 
The  remainder  of  the  drag  is  filled  in,  rammed  and 
vented.  The  flask  may  now  be  turned  over  and  the  joint 
slicked  as  before.  The  other  half  of  the  pattern  is  put 
on  as  shown  in  Fig.  24.  Parting  sand  is  put  over  the 


Fig.  23. 


joint,  then  the  cope  is  placed  in  position.  Pulleys  and 
wheels  should  always  be  poured  from  the  hub,  so  the 
gate  stick  must  be  placed  above  the  hub.  The  facing 
sand  is  put  on  the  arms  and  hub,  and  riddled  sand  filled 
in  over  the  pattern.  Soldiers  may  now  be  placed  in  the 
same  manner  as  in  the  drag,  but  their  office  in  this  place 
is  mere  to  hold  the  sand  from  falling  away  when  the 
cope  is  lifted  off  or  closed  after  removing  the  pattern. 


64 


FOUNDRY  PRACTICE 


FOUNDRY  PRACTICE 


r>5 


The  first  ramming  is  the  same  as  the  drag,  then  the  gate 
stick  may  be  put  in  place  and  the  ramming  finished.  The 
cope  is  vented,  the  pouring  basin  cut  and  the  gate  stick 
removed  giving  the  flask  in  form  as  shown  in  Fig.  25. 
The  cope  is  lifted  off  and  placed  on  any  convenient  block- 
ing, as  shown  in  Fig.  26.  The  pattern  in  the  cope  is 
brushed  off  and  lightly  swabbed  with  water. 

The  pattern  is  rapped  and  removed,  by  lightly  jarring 
as  it  is  drawn.  The  gate  is  reamed  a  little  at  the  hub  to 
remove  loose  sand,  then  the  hub  and  arms  are  slicked 
and  blackened  with  plumbago.  The  drag  is  prepared  in 
the  same  manner,  then  the  flask  is  ready  to  close  and 
clamp  for  casting. 


Fig.  27 

Many  patterns  have  rounded  edges  or  have  the  point 
of  parting  located  at  different  levels  in  various  parts  of 
the  pattern.  In  these  cases  the  parting  on  th,e  drag  must 
be  shaped  to  allow  the  pattern  to  be  withdrawn  without 
destroying  the  shape  or  tearing  up  the  sand.  The  upper 
portion  of  the  pattern  must  be  formed  in  the  cope.  This 
causes  a  portion  of  the  sand  to  be  hung  in  the  cope  below 
the  level  of  the  flask,  or  the  sand  is  coped  out  to  the  pat- 
tern. In  cases  of  coping  out,  a  portion  of  the  sand  is 
lifted  from  the  pattern  when  the  cope  is  lifted  off.  This 
does  not  admit  of  rapping  the  pattern  or  otherwise  loos- 
ening the  sand,  therefore  the  sand  must  be  well  anchored 


66 


FOUNDRY  PRACTICE 


so  as  to  hold  its   form  well  and  not  require  too  much 
patching. 

The  pattern  of  the  half  of  an  eccentric  strap,  shown 
in  Fig.  27,  may  be  taken  as  an  example  where  coping 
out  is  necessary.  The  pattern  can  not  be  drawn  side- 
wise,  as  the  inner  circle  has  a  flange  on  each  side. 


Fig.  28. 

To  cast  this  eccentric  strap,  the  pattern  is  placed  in 
the  drag  with  the  inner  circle  toward  the  turn-over 
board,  then  facing  is  put  on  the  pattern  and  the  drag 
filled,  rammed,  vented,  and  turned  over  as  in  previous 
cases.  The  parting  is  now  made  even  with  the  face  of 
the  drag  at  each  end  up  to  the  edge  of  the  inner  circle. 


FOUNDRY  PRACTICE  67 

The  part  then  follows  the  outer  edge  of  the  pattern  and 
the  sand  is  sloped  outward  on  each  side,  as  shown  in 
Fig.  28.  This  slope  must  be  so  as  to  allow  the  sand  to 
part  freely  at  all  points  when  the  cope  is  lifted.  The 
dry  parting  sand  is  then  placed  over  the  level  portion  ot 
the  drag,  but  it  will  not  stay  on  the  slope.  A  good  part- 
ing sand  for  that  part  is  fine  new  sharp  sand  dampened 
and  spread  in  a  thin  coating  over  the  slope  by  slicking  on 
with  a  trowel  or  the  hand ;  over  this  dust  the  dry  parting 
sand. 

The  cope  for  a  pattern  like  this  must  "have  special 
bars  following  near  to  the  shape  of  the  pattern,  as  shown 
in  Fig.  29.  The  bars  must  be  dampened  with  clay  wash 
or  thin  flour  paste  to  make  the  sand  stick  to  the  bars. 

Facing  is  riddled  onto  the  pattern  and  sand  riddled 
over  the  drag  to  a  depth  of  about  one-half  inch.  The 
flask  joint  is  then  cleared  and  the  cope  is  put  in  place. 
The  gate  stick  is  placed  opposite  the  centre  of  one  end, 
while  a  riser  is  placed  at  the  other.  The  offices  of  the 
riser  are  to  allow  the  gases  to  escape  from  the  mold  and 
to  furnish  iron  to  feed  the  casting  when  shrinkage  takes 
place. 

Gaggers  are  then  set  in  the  cope,  observing  the  pre- 
cautions previously  given,  and  are  placed  near  enough 
together  to  anchor  the  sand  firmly  in  the  cope.  The 
sharp  edge  coming  inside  of  the  llanges  may  be  better 
anchored  by  placing  nails  with  heads  toward  the 
pattern  at  intervals  of  about  one  to  two  inches.  The 
nail  heads  should  be  clay-washed  and  set  as  soldiers. 
Sand  is  now  riddled  into  the  cope  to  a  depth  of  two  or 
three  inches,  then  the  bars  are  tucked  with  the  fingers  to 
harden  the  sand  under  the  bars,  the  same  as  the  rammed 
portion  between  the  bars.  Sand  is  filled  in  to  a  depth  of 


Fig.  29. 


FOUNDRY  PRACTICE  69 

about  6  in.  The  part  enclosed  between  each  set  of 
bars  is  rammed  separately,  similarly  to  an  individual  cope, 
but  using  care  to  have  all  the  divisions  rammed  to  an 
even  hardness.  The  remainder  of  the  cope  is  then  filled 
in  and  rammed,  having  about  6  to  8  in.  of  sand 
to  a  ramming,  until  the  cope  is  entirely  filled,  when  it  is 
butted  off  and  vented.  In  ramming,  the  operator  must 
avoid  striking  the  gaggers,  as  that  -drives  them  into  the 
drag  and  then  necessitates  patching  when  the  cope  is 
lifted  off.  The  cope  may  now  be  lifted  off,  using  care 
to  lift  it  slowly  and  evenly  in  order  that  the  sand  may 
not  be  torn  by  striking  at  any  point.  The  cope  should  be 
gone  over  with  the  hand  to  see  if  there  are  any  soft  spots, 
which  when  found  should  be  filled  to  an  even  hardness 
with  other  parts.  It  is  then  patched  where  necessary  and 
slicked  to  a  smooth  surface.  The  pattern  is  drawn  from 
the  drag  after  removing  all  the  parting  sand  and  swab- 
bing the  sand  at  the  edge  of  the  pattern.  The  mold  is 
slicked  and  the  gate  and  riser  connected  to  the  mold  by 
the  runner.  This  gives  the  mold  in  the  form  as  shown 
in  Fig.  30.  The  mold  may  be  blackened  and-  closed, 
ready  to  be  cast. 

Many  patterns  are  of  such  form  that  they  require  a 
special  follow  board  or  match  in  order  to  mold  them  -by 
turning  over.  When  there  are  not  enough  castings  re- 
quired to  pay  to  make  a  follow-board,  other  means  must 
be  resorted  to.  If  these  are  of  such  form  that  they  may 
be  evenly  rammed  by  bedding  in,  that  method  often 
saves  much  time. 

To  mold  by  bedding  in  is  to  place  the  drag  in  the  po- 
sition it  is  to  have  when  the  cope  is  put  on,  then 
ram  the  sand  in  until  it  is  of  such  a  height  as  to  bring 
the  parting  of  the  pattern  at  the  parting  of  the  flask,  and 


FOUNDRY  PRACTICE 


FOUNDRY  PRACTICE 


finish  the  ramming  of  the  drag  with  the  pattern  in  posi- 
tion. Many  forms  of  patterns  easily  admit  of  this  method, 
in  that  there  are  no  parts  that  are  not  easily  accessible 
for  ramming  the  sand  from  the  top  side.  Other  patterns 
may  be  such  that  a  molder  may  easily  patch  any  soft 
spots  that  are  under  the  pattern  when  finishing  the  mold. 
In  some  places  the  main  portion  of  the  molding  is 
done  by  this  method,  but  on  the  majority  of  patterns  it  is 
easier  and  quicker  to  prepare  the  drag  by  turning  over. 
In  England  where  iron  flasks  are  used,  the  main  method 


?  P 


Fig.  31. 

used  is  that  of  bedding  in,  due  to  the  weight  and  to  dif- 
ficulty in  turning  over  the  flask. 

The  molder  must  use  his  discretion  in  deciding  which 
method  he  should  use  in  order  to  save  time  and  labor. 
Different  men  making  the  same  pattern  may  be  able  to 
do  the  best  and  quickest  work  by  using  opposite  methods, 
according  as  each  is  most  accustomed. 

One  type  of  castings  that  may  best  be  made  by  bed- 


72  FOUNDRY  PRACTICE 

ding  in  may  be  illustrated  by  the  making  of  a  large  plain 
plate  by  use  of  the  frame  shown  in  Fig.  31.  The  pat- 
tern is  made  in  frame  so  as  to  be  able  easily  to  ram  the 
sand  that  comes  under  it.  The  narrow  frame  may  easily 
be  tucked  to  the  required  hardness,  while  if  a  solid  pat- 
tern be  used  an  even  hardness  is  much  more  difficult  to 
obtain. 

In  making  the  mold,  the  drag  is  placed  on  the  bottom 
board  in  the  position  to  receive  the  cope.  Sand  is  shov- 
elled in  and  rammed  to  a  depth  that  will  hold  the  top  of 
the  pattern  nearly  to  a  level  of  the  parting  of  the  flask. 
Sand  is  then  riddled  into  the  drag  to  a  sufficient  depth 
for  putting  the  pattern  in  place  and  tucking  the  sand 
firmly  under  it.  The  pattern  is  placed  in  position  and 
forced  to  the  level  of  the  drag,  then  it  may  be  held  bv 
placing  a  weight  on  it  to  avoid  raising  while  tucking  sand 
under  it  at  the  soft  places.  The  remainder  of  the  drag 
is  rammed  to  the  parting.  The  drag  is  well  vented  be- 
fore making  the  parting,  to  close  the  top  of  the  vents, 
thus  forcing  the  gases  out  at  the  bottom  board.  The 
cope  is  placed  on,  rammed,  and  lifted  by  observing  the 
precautions  previously  given. 

In  order  to  make  a  plate  of  the  mold,  the  sand  within 
the  frame  must  be  taken  out  to  a  depth  equal  to  that  of 
the  pattern.  In  order  to  make  this  of  even  depth,  a 
strike  stick  as  shown  at  A,  Fig.  31,  is  used  to  strike  out 
the  sand.  The  pattern  is  then  removed  and  the  surface 
is  slicked  to  an  evenness,  using  care  not  to  cause  hard 
spots.  The  mold  may  now  be  blackened  and  runners  cut, 
when  it  is  ready  to  close. 

When  a  mold  is  made  in  the  sand  on  the  floor  without 
a  cope  to  cover  it,  it  is  called  open  sand  molding.  This 
is  a  cheap  form  of  molding  for  some  types  of  castings. 


FOUNDRY  PRACTICE 


73 


The  casting  will  not  be  clean  or  smooth  but  may  have  its 
exact  form  all  except  the  upper  surface. 

This  method  may  be  used  for  making  castings  for 
parts  of  iron  flasks,  clamps,  core  irons,  floor  plates,  or 
castings  whose  upper  sides  may  be  rough  and  where  the 
exact  thickness  of  metal  is  not  important. 

Many  of  the  precautions  necessary  to  obtain  a  good 
casting  from  open  sand  work  may  be  noted  in  the  pro- 
cedure for  making  the  flask  bar  shown  in  Fig.  32.  The 
manner  of  making  molds  of  this  style  varies,  as  is  mos: 


Fig.  32. 

convenient  with  the  material  the  molder  has  at  hand. 
The  method  given  below  is  most  flexible  and  may  be 
used  on  a  great  variety  of  patterns.  Particular  cases  may 
be  handled  in  very  different  manner. 

The  top  surface  of  the  pattern  must  be  level  in  al1 
directions,  for  the  metal  when  poured  is  a  liquid  which 
seeks  its  level.  The  metal  lies  on  the  sand  with  only  the 
thickness  of  the  casting.  Since  there  is  no  head,  as  in 
gates  and  risers,  to  give  a  pressure,  the  sand  must  be 
open  and  well  vented  to  give  a  free  escape  to  the  gases. 


74  FOUNDRY  PRACTICE 

or  they  will  force  through  the  iron  and  cause  the  sand 
to  cut  away,  making  a  bunch  on  the  casting  or  leaving 
blow-holes  through  the  iron. 

The  pattern  here  shown  has  the  lower  face  a  plane  ex- 
cept for  the  flanges  at  each  end.  We  may  therefore 
make  a  level  bed  and  place  the  pattern  onto  it.  To  make 
the  bed,  two  straight  pieces,  preferably  T  rails,  are 
placed  on  the  floor  and  leveled.  One  piece  is  placed 
down  and  leveled  with  a  spirit  level,  then  'the  other  is 
laid  parallel  with  it  at  a  distance  that  will  give  ample 
room  to  locate  the  pattern,  with  the  pouring  basin  coming 
at  the  edge  of  the  bed.  This  piece  is  made  level  with 
the  first  by  use  of  a  straight  edge  resting  on  each  piece 
and  the  level  on  the  upper  parallel  edge  of  the  straight 
edge.  Sand  is  filled  in  almost  to  the  top  of  the  pieces  and 
rammed  lightly  to  an  even  hardness.  The  remainder  is 
filled  with  riddled  sand  and  rammed  lightly.  Unless  the 
sand  is  very  open,  the  bed  should  be  well  vented  down- 
ward with  cross  vents,  allowing  the  gas  to  escape  to  tht 
sides.  The  bed  is  then  struck  off  with  a  straight  edge 
resting  on  the  leveled  pieces,  thus  giving  an  even  and 
level  bed. 

The  pattern  is  then  placed  on  the  bed  in  the  position 
most  convenient  for  pouring.  It  may  be  driven  down 
part  the  depth  of  the  flange,  then  drawn  out  and  the  de- 
pression of  the  flanges  cut  with  a  trowel  to  soften  the 
sand,  to  avoid  its  becoming  too  hard  when  the  pattern  is 
forced  down  to  the  bed.  The  pattern  is  replaced  and 
forced  down  to  a  bearing  on  the  bed.  The  edges  may 
then  be  tucked  a  little  to  harden  the  sand  on  which  the 
edges  rest.  Sand  is  filled  in  and  tucked  with  the  hands 
around  the  pattern  until  the  sand  is  above  the  top  of  the 
pattern.  The  top  is  struck  off  even  with  the  pattern  by 


FOUNDRY  PRACTICE 


75 


any  short  straight  edge,  and  the  surface  slicked  with  a 
trowel.  The  pouring  basin  may  be  built  at  the  end  by 
making  a  U-shaped  mound  of  sand  with  the  enclosed  por- 
tion tapering  down  away  from  the  edge  of  the  pattern. 
The  object  of  this  depression  is  to  hold  some  metal  on 
which  the  inflowing  metal  strikes  instead  of  on  the  sand. 
The  pattern  may  be  removed  from  the  mold  after 
swabbing  the  edge  and 'rapping  to  free  the  sand.  The 
bottom  is  slicked  smooth  with  the  trowel,  care  being  used 


Fig.  33- 

not  to  make  hard  spots.  The  flange  may  be  patched  to 
proper  shape  whenever  necessary,  then  the  mold  is  ready 
to  receive  the  metal. 

In  the  case  of  coring  holes  through  the  plate,  the 
prints  may  be  on  the  lower  side  of  the  pattern  when 
placed  on  the  bed.  The  cores  near  to  the  entering  metal 
should  be  supported  by  nails  to  avoid  washing  out  by 


FOUNDRY   PRACTICE 


FOUNDRY  PRACTICE  77 

the  flow  of  the  metal.  It  is  a  good  plan  to  put  a  few 
nails  at  the  edge  next  to  the  basin  to  avoid  its  breaking 
in  when  poured. 

Many  castings  require  dry  sand  cores  for  making 
holes  and  openings  in  the  castings  that  are  solid  in  the 
pattern.  In  these  cases  the  pattern  has  a  print  which  lo- 
cates the  core  and  holds  it  in  position  in  the  mold.  The 
core  must  be  vented  off  in  the  mold  to  allow  the  gases  to 
escape  freely.  It  must  be  properly  anchored  by  bearing 
on  the  sand  or  by  chaplets  to  prevent  its  floating  when 
the  iron  surrounds  it  in  pouring. 

Some  of  the  principles  involved  in  setting  cores  are 
illustrated  in  making  the  casting  shown  in  Fig.  33.  This 
is  the  casting  for  a  headstock  whose  body  part  is  hollow 
and  having  the  bearings  cored  for  babbit. 

The  pattern  used  is  shown  in  Fig.  34.  This  is  a  one- 
part  pattern  having  loose  pieces  for  the  projecting  parts. 
In  this  case  the  loose  pieces  are  held  in  place  by  a  dove- 
tail. Usually  loose  pieces  are  pinned  onto  the  pattern. 
In  cases  where  loose  pieces  are  pinned  on,  the  sand  is 
rammed  around  the  loose  piece,  then  the  pin  is  drawn, 
leaving  it  free  from  the  pattern  when  it  is  withdrawn 
from  the  mold. 

The  drag  and  cope  are  rammed  in  the  usual  manner 
of  a  common  mold.  When  the  pattern  is  drawn  from  the 
drag,  the  loose  pieces  remain  in  position  in  the  sand;  as 
at  T,  Fig.  35.  The  mold  should  be  patched  and  finished 
before  drawing  the  loose  pieces.  The  edge  of  the  large 
pieces  should  be  nailed  with  short  nails  to  prevent  tearing 
or  dropping  when  the  piece  is  removed.  The  nails  should 
be  slanted  away  from  the  pattern  and  pressed  in  so  the 
head  comes  even  with  the  surface.  The  loose  piece  is 
then  loosened  from  the  sand  by  rapping,  and  drawn  into 


FOUNDRY  PRACTICE 


CQ 


I 


FOUNDRY  PRACTICE  79 

the  mold,  as  at  B,  Fig.  35.  These  new  parts  are  then 
finished  and  the  mold  may  be  blackened  all  over. 

The  cores  are  placed  into  the  mold  after  the  manner 
shown  in  Fig.  36.  The  cores  are  vented  ofl  at  the  bot- 
tom by  running  a  vent  wire  down  from  the  print,  then 
inserting  another  wire  on  the  bottom  board  to  strike 
the  former.  Several  vents  must  be  made  in  this  manner 
to  ensure  free  escape  of  the  gases.  This  being  a  com- 
pound core,  those  at  the  bottom  must  be  set  first.  The 
small  bearing  cores  go  into  the  opening  left  by  the  print 
on  the  loose  pieces  A  and  B,  Fig.  35.  The  main  core  has 
a  bearing  on  each  of  these  cores  and  is  held  in  place  by 
the  side  of  the  mold  which  was  formed  by  the  main  print 
of  the  pattern. 

The  upper  vents  of  the  core  should  be  closed  with 
sand  or  flour  to  prevent  the  metal  flowing  into  the  vent 
if  it  should  get  above  the  core.  The  print  in  the  cope 
holds  the  upper  side  of  the  core  in  position,  thus  pre- 
venting the  liability  of  moving  sidewise  when  the  mold 
is  cast.  The  mold  may  be  closed  when  the  gates  and  run- 
ners are  properly  cut. 

Many  patterns  are  of  such  form  that  they  can  not  be 
drawn  from  a  two-part  flask,  in  which  case  an  intermed- 
iate portion  called  a  cheek  is  required.  This  branch  of 
molding  is  generally  known  as  three-part  work.  The 
flask  used  and  the  methods  of  procedure  are  dependent 
upon  the  pattern.  These  are  greatly  varied. 

To  illustrate -one  of  the  general  forms  using  a  "plain 
cheek,"  we  have  taken  for  an  example  the  piston  spider 
for  a  Corliss  engine,  shown  in  Fig.  37.  The  pattern,  as 
shown  in  Fig.  38,  is  in  two  parts.  The  main  or  body  con- 
sists of  the  outside  ring  as  shown  in  the  figure.  The 
other  portion  consists  of  the  centre  hub  with  web  con- 


8o 


FOUNDRY  PRACTICE 


FOUNDRY  PRACTICE 


81 


necting  it  to  the  ring.  The  bosses  in  the  pockets  are 
loose  and  dowelled  onto  the  body  portion  of  the  pattern. 
To  ensure  a  firm,  clean  casting,  it  is  advisable  in  this 
case  to  run  some  metal  through  the  mold  after  it  is  filled. 
The  mold  is  poured  from  the  bottom,  thus  providing  a 
skim  gate  and  allowing  the  metal  to  rise  in  the  mold 


Fig.  37- 

without  flowing  across  the  overhanging  portion  of  the 
cheek. 

To  form  the  mold,  the  pattern  is  placed  on  the  fol- 
low-board  with  all  the  parts  in  place.  Facing  sand  is  put 
into  the  pockets  to  a  depth  of  about  2  in.  Long 
rods  are  placed  in  the  pockets  to  securely  anchor  them 
in  the  cope.  Fill  in  about  2  in.  more  of  facing  and  ram 
lightly  with  a  rod  or  stick,  using,  care  to  avoid  making 
the  sand  too  hard.  The  remainder  of  the  pocket  is  filled 
and  rammed.  The  dowels  mav  be  removed  from  the 


82 


FOUNDRY  PRACTICE 


FOUNDRY  PRACTICE  83 

bosses.  The  pockets  should  now  be  thoroughly  vented, 
using  a  needle  wire  smaller  than  1/16  in.  in  diameter. 

The  cheek  may  be  placed  on  the  follow  board  about 
the  pattern.  The  gate  stick  is  placed  in  its  position  out- 
side of  the  pattern.  The  cheek  is  now  rammed  and  the 
parting  made  at  the  upper  edge  of  the  ring.  The  cope 
may  be  placed  upon  the  cheek.  The  pouring  gate  from 
the  cheek  extends  through  the  cope,  and  a  flow-off  gate 
is  placed  on  the  centre  hub  beside  the  centre  core.  The 
cope  is  rammed,  ensuring  proper  anchorage  for  the  rods 
from  the  pockets.  It  should  be  well  vented,  especiallv 
above  the  pockets.  The  gate  sticks  are  then  removed.  A 
bottom  board  is  placed  upon  the  cope,  the  flask  firmly 
clamped  together,  and  the  whole  turned  over.  The  fol- 
low-board  is  removed  and  the  lower  parting  made  on  the 
cheek. 

The  core  print  is  placed  on  the  pattern.  The  drag  is 
rammed,  having  proper  anchorage  for  lifting  it  off.  Af- 
ter venting  the  drag  is  lifted  off  and  placed  on  a  bot- 
tom board  bedded  for  receiving  the  flask.  The  drag  is 
slicked  and  finished.  The  surface  directly  in  front  of  the 
gate  is  nailed  to  prevent  the  iron  from  cutting  away  the 
sand. 

The  body  portion  of  the  pattern  is  drawn  from  the 
flask.  The  top  of  the  cheek  is  finished  and  the  runner 
cut  to  connect  with  the  pouring  gate.  The  cheek  is  lift- 
ed off  and  completely  finished  and  blackened,  then  placed 
in  its  position  on  the  drag.  Before  removing  the  second 
portion  of  the  pattern  from  the  cope,  the  edges  of  the 
pockets  should  be  well  nailed  to  better  anchor  the  sand. 
The  pattern  may  now  be  drawn  and  the  cope  finished  and 
blackened.  After  setting  the  centre  core,  the  flask  may 
be  closed.  The  gate  sticks  are  replaced  in  their  respec- 


84  FOUNDRY  PRACTICE 

live  positions,  in  order  to  form  the  overflow  runner  and 
the  pouring  basin  which  must  be  higher  than  the  flow-off 
gate.  To  prevent  closing  the  vents  in  the  cope,  when 
the  flow-off  gate  is  made,  the  surface  is  covered  with 
paper,  hay,  or  any  convenient  material.  ^  The  gate  is 
made  having  a  runner  to>  conduct  the  overflow  from  the 
flask.  After  clamping  it  is  ready  to  receive  the  metal. 

In  some  cases  it  is  found  that  dirt  accumulates  in  the 
flange  directly  above  the  gate  where  the  metal  enters. 
It  acts  as  a  whirl  or  retaining  point  that  is  not  forced 
to  circulate  as  the  metal  is  flowing-  into  the  mold.  To 
avoid  this,  it  is  advisable  to  put  a  top  gate  on  the  opposite 
side  of  the  centre  core  from  the  flow-off  gate. 

Many  forms  of  patterns  requiring  three-part  flasks 
are  such  that  the  "cheek  can  not  be  lifted."  In 
such  cases  the  lower  portion  of  the  pattern  is  drawn  and 
that  part  of  the  mold  finished  before  the  drag  and  cheek 
are  rolled  over. 

The  lathe  bed  castin'g  shown  in  Fig.  39  gives  a  good 
example  of  this  class  of  work.  The  pattern  has  the  two 
upper  rails  loose  with  the  fillets  attached  forming  the 
guides  to  hold  them  in  place. 

This  casting  may  best  be  gated  so  as  to  allow  the  met- 
al to  enter  at  both  top  and  bottom  rails  thus  reducing 
the  liability  of  the  metal  cutting,  from  too  great  a  flow 
at  the  bottom  or  by  falling  from  the  top  of  the  mold. 

The  cheek  is  placed  on  the  follow-board  and  the  pat- 
tern placed  with  the  cope  side  down,  in  which  case  the 
loose  rails  come  on  the  upper  side.  The  gate  stick  is 
placed  in  position  so  that  runners  may  be  cut  to  the  low- 
er rails.  The  pattern  is  then  faced  on  the  outside  and 
rammed  in  the  usual  manner.  The  inner  portion  will 
be  a  green  sand  core  which  is  separate  from  the  flask  and 


FOUNDRY  PRACTICE 


has  bearing  at  top  and  bottom.  In  the 
centre  of  each  should  be  placed  a  vent 
rod  to  give  a  conduct  for  carrying  off 
the  gases.  The  sand  is  filled  in  and 
rammed  to  a  depth  of  about  four  inches. 
Rods  are  now  laid  in  diagonally  to  bind 
the  sand  together.  Use  facing  next  to  the 
pattern  and  riddled  sand  for  the  remain- 
der. Each  succeeding  ramming  of  from 
2  to  4  in.  should  be  well  rodded,  laying 
them  in  different  directions  each  time. 
When  the  cross  webs  of  the  pattern  are 
covered,  it  is  best  to  place  two  or  three 
long  rods  in  to  bind  the  whole  core  to- 
gether. 

When  the  cheek  is  finished  the  parting 
is  made  even  with  the  top  of  the  pattern. 
The  face  of  this  parting  should  be  hard- 
er than  in  the  previous  cases,  because  the 
pressure  head  of  the  metal  is  very  great 
as  this  comes  at  the  bottom  of  the  mold. 
A  good  method  of  getting  this  parting  of 
even  hardness  is  to  riddle  some  sand  on- 
to the  surface  to  a  depth  of  about  2  in., 
then  butt  in  firmly  but  not  hard. 

Strike  it  off  with  a  stick,  then  slick 
with  a  trowel  after  riddling  on  a  little 
sand  over  the  entire  surface.  The  gate 
stick  should  come  to  this  surface  but  not 
extend  beyond.  Parting  sand  is  put 
on  and  the  drag  rammed,  vented  and 
lifted  off. 


0 


86  FOUNDRY   PRACTICE 

The  cheek  should  be  well  vented  on  the  outside  of 
the  pattern  and  under  the  rail  that  is  about  to  be  drawn. 
These  vents  should  be  led  off  to  the  parting  of  the  flask. 
The  centre  portion  should  have  vent  gutters  cut  around 
within  about  2  in.  of  the  pattern  and  leading  to  the  centre 
vent  rod  of  each  of  the  cores.  The  vents  are  all  made  to 
extend  from  this  gutter.  The  wire  should  be  y%  or  3/10 
in.  in  diameter.  Vent  particularly  under  the  rails  and 
around  the  centre  web. 

The  parts  of  the  pattern  are  drawn.  The  edges  of 
the  fillets  near  the  web  or  the  part  of  the  pattern  still 
remaining  in  the  mold  should  be  nailed,  using  lo-d.  nails 
and  placing  them  about  2  in.  apart.  The  mold  is  theii 
slicked,  blackened,  and  gates  cut  from  the  rails  to  the 
gate  stick.  The  drag  is  then  closed  onto  the  cheek.  Sand 
should  be  thrown  onto  the  top  and  struck  off  evenly. 
This  may  be  easily  accomplished  by  using  a  straight 
edge  with  a  gagger  or  strip  of  wood  under  it  and  bearing 
on  the  flask.  The  bottom  board  is  placed  on  and  rubbed 
to  good  bearing,  then  the  flask  is  clamped  together  firm- 
ly and  turned  over,  using  care  not  to  strain  the  mold. 
The  follow-board  is  removed  and  the  upper  parting  mad<. 
on  the  cheek. 

The  cope  is  then  rammed,  having  a  riser  opposite  the 
gate  and  the  vent  rods  drawn  up  to  give  opening  through 
the  cope.  This  is  lifted  off  and  finished  in  the  usual 
manner.  The  cheek  is  vented  under  the  rails  on  the  out- 
side of  the  pattern  and  the  vents  led  off  to  the  parting. 
In  venting,  do  not  endanger  forcing  the  wire  into  the 
lower  part  of  the  mold  where  the  pattern  has  been  re- 
moved. In  the  centre  portion,  vent  gutters  should  be  cut 
around  each  core  and  led  to  the  centre  vent;  then  vent 
the  core  to  lead  to  these  gutters.  The  pattern  may  now 


FOUNDRY  PRACTICE  87 

be  drawn  and  the  mold  slicked  and  blackened.     Runners 
are  cut  to  connect  the  rails  to  the  main  gate.     The  cope 


Fig.  40. 


J     i 


may  be  closed,  the  pouring  basin  made,   and  the  riser 
built  to  the  same  height. 


Fig.  41. 


In  this  mold  there  is  a  depth  of  metal  which  causes  a 
pressure  against  the  side.     This  must  be  provided  for  in 


88 


FOUNDRY  PRACTICE 


clamping  the  mold.  A  tie  clamp  may  be  placed  over  the 
flask,  having  the  parallel  ends  long  enough  to  reach  to 
the  bottom  of  the  cheek.  Wedges  are  placed  between  the 
clamp  and  the  flask,  and  forced  to  a  firm  bearing,  but 
must  not  spring  the  flask.  These  may  be  driven  in  hard 
enough  by  striking  with  a  hammer  handle.  In  these  cas- 


Fig.  42. 

es,  be  very  careful  not  to  put  great  pressure  at  the  sides, 
for  the  flask  will  be  forced  together,  making  the  metal  of 
the  web  too  thin  or  making  it  cut  through  to  the  cheek. 
In  making  many  castings  much  time  may  be  saved 
by  making  "three-part  work  in  two-part  flasks."  This 
may  be  accomplished  by  using  a  cover  core  over  the  bot- 
tom division  of  the  mold  when  that  is  a  plane  surface. 


In  other  cases  the  cheek  portion  may  be  made  in  the  sand 
alone.  This  latter  form  may  be  shown  by  the  sheave- 
wheel  made  from  the  pattern  shown  in  Fig.  40.  There 
are  two  other  methods  of  making  this,  and  the  method 
chosen  depends  mainly  upon  the  size  of  the  wheel  to  be 


Fig.  43- 

made.  Fig.  41  represents  a  three-part  flask  with  the 
cheek  so  it  may  be  lifted.  Fig.  42  is  a  two-part  flask 
having  the  third  or  cheek  made  in  core.  After  the  pat- 
tern is  drawn  out,  cores  of  the  form  shown  at  A  are  set 
in  the  place  of  the  print  on  the  pattern.  This  method  is 


Fig.  44- 

of  great  convenience  when  there  are  two  or  more  grooves 
in  place  of  the  single  groove  here  represented.  The  pat- 
tern is  made  in  halves  as  shown  in  Fig.  40.  The  process 
of  molding  would  be  to  ram  the  cope  as  usual  with  the 
pattern  in  the  centre  of  the  flask  as  shown  in  Fig.  43, 
having  the  gate  stick  placed  on  the  hub.  The  flask  is 


90  FOUNDRY  PRACTICE 

turned  over  and  the  parting  made  to  slope  down  to  the 
parting  line  of  the  pattern  as  shown  in  Fig.  44.  The  oth- 
er half  of  the  pattern  is  put  in  place  and  weighted  so  as 
to  ensure  its  remaining  in  place  while  the  cheek  is  made. 
The  cheek  is  made  by  tucking  in  about  the  pattern  until 
filled  so  as  to  make  the  upper  parting  as  shown  in  Fig. 
45.  The  drag  may  now  be  put  ni  place  and  rammed.  It 
must  be  sufficiently  anchored  to  allow  lifting  off. 

The  drag  is  then  lifted  off  and  that  half  of  the  pat- 
tern drawn  and  the  mold  slicked  and  finished,  as  shown 
in  Fig.  46.  The  drag  is  replaced,  and  the  bottom  board 
given  a  firm  bearing  by  use  of  loose  sand  on  the  flask, 


'   Fig.  45- 

then  turned  over  carefully  onto  the  bed  where  it  is  to  re- 
main. The  cope  is  now  lifted  and  the  remainder  of  the 
pattern  drawn  and  the  mold  finished.  In  lifting  a  part 
of  the  flask  where  the  pattern  is  lifted  with  it,  a  draw 
spike,  or  wood  screw,  should  be  put  into  the  pattern  and 
held  when  the  flask  is  lifted.  The  centre  core  is  set, 
then  the  mold  may  be  closed.  A  pouring  basin  should 
be  built  on  the  runner  so  that  the  iron  may  strike  in  the 
basin  instead  of  directly  into  the  gate.  This  breaks  the 
fall  of  the  iron  from  the  ladle  and  relieves  the  straining 
pressure  on  the  mold,  besides  acting  as  a  skim  gate  when 
the  basin  is  kept  full.  The  dirt  and  slag  float  on  top, 


FOUNDRY  PRACTICE 


92  '  FOUNDRY  PRACTICE 

while  the  clean  metal  enters  the  mold  from  the  bottom 
of  the  basin.  This  gives  the  mold  as  shown  in  Fig.  47. 

The  use  of  cores  for  covering  part  of  the  mold  in- 
stead of  a  third  part  to  the  flask  is  found  to  be  of  great 
advantage  when  making  large  baseplates  for  columns. 
Fig.  48  shows  a  baseplate  casting  which  may  be  made  by 
use  of  cover  cores. 

The  pattern  for  this  casting  has  the  top  and  bottom 
pieces  dowelled  to  the  centre  piece  and  the  ribs,  while  the 
ribs  are  also  separate  from  one  another.  The  pattern  in 


Fig.  47- 

its  complete  form  is  placed  on  the  follow-board  in  the 
drag.  The  bottoms  of  the  pockets  are  faced  and  filled 
with  sand  to  a  depth  of  about  3  in.  This  is  rammed 
lightly,  then  long  rods  are  laid  in  horizontally,  extending 
out  to  the  flask.  Two  rods  should  be  placed  in  near  the 
corner  of  each  pocket  and  slanting  upward  to  just  allow 
room  for  the  cores  to  be  placed  on  the  top  without  strik- 
ing the  rods.  These  rods  should  not  strike  the  pattern. 
The  buoyancy  of  the  metal,  acting  on  the  bottom  of  the 
sand  which  forms  the  pocket,  is  held  by  these  rods  placed 


FOUNDRY  PRACTICE 


Fig.  48. 


94  FOUNDRY  PRACTICE 

in  the  sand.  This  buoyancy,  or  lifting  force,  acts  on  the 
surface  exposed  by  the  lower  plate  proportionally  to  the 
area  exposed  and  the  height  of  the  pressure  head.  About 
3  or  4  in.  of  sand  is  filled  into  the  pockets  and  rammed 
about  the  rods  with  a  small  rammer,  care  being  used  to 
have  the  rods  firmly  rammed  into  place  and  not  sprung 
so  as  to  tear  the  mold  when  the  pattern  is  drawn.  This 
should  be  well  vented  in  the  pockets  and  a  coke  bed  for 
collecting  the  gases  laid  into  the  pockets  and  leading  to 
the  flask  where  the  gases  may  escape.  The  coke  bed  is 
covered  with  sand  to  a  depth  for  ramming,  then  a  num- 
ber of  rods  should  be  laid  in  horizontally  as  before. 

Much  time  may  be  saved  in  molding  if  cores  are  made 
to  fit  the  pockets  next  to  the  top  plate  and  of  a  thickness 
of  about  2  in.  These  cores  should  extend  out  to  a  dis- 
tance of  3  in.  beyond  the  plate  B.  This  prevents  the 
green  sand  from  breaking  when  turned  over.  The  sand 
below  the  cores  should  be  well  vented  to  the  coke  bed 
and  have  a  firm,  even  bearing  all  over.  When  no  cores 
are  ifsed,  rods  should  be  laid  in  near  to  the  plate  and  the 
sand  well  rammed  and  vented  to  the  coke  bed.  After  re- 
moving the  plate  the  edges  should  be  well  nailed  before 
replacing  the  cover  core. 

The  flask  is  now  filled  to  the  plate  B.  This  is  left  in 
place  and  sand  rammed  in  and  a  surface  made  even  with 
the  top  of  pattern.  When  a  special  cover  core  is  used, 
it  should  be  put  in  place  determined  by  the  centre  print 
and  the  edges  marked  in  the  sand  and  guide  rods  placed 
at  the  corners  to  ensure  replacing  to  the  proper  position. 
The  core  is  now  lifted,  the  pattern  drawn  and  the  mold 
finished  in  this  portion.  The  cover  core  is  replaced  and 
the  remainder  of  the  drag  filled,  rammed,  and  vented, 
ready  to  turn  over. 


FOUNDRY  PRACTICE  95 

When  no  special  cover  core  is  provided,  an  extra  piece 
may  be  made  for  the  pattern  coming1  to  the  edges  marked 
C  in  the  figure.  This  may  be  drawn  from  the  other  side 
of  the  mold.  In  this  case,  after  the  surface  is  made  even 
with  the  top  of  the  pattern,  the  plate  B  is  drawn  and  this 
piece  is  placed  on  the  pattern  with  the  centre  print.  Stock 
slab  cores  may  be  used  to  cover  the  mold  in  the  place 
of  the  cover  core. 

The  drag  is  turned  over,  the  parting  made,  and  the 
cope  rammed,  having  a  gate  at  the  centre  of  one  side  and 
a  riser  at  another  side.  The  large  plate  A  is  drawn  first 
and  the  faces  of  the  pockets  finished.  The  front  corners 
should  be  nailed  with  large  nails  and  a  few  placed  along 
the  sides  to  prevent  the  sand  from  cutting,  cracking  off, 
or  scabbing  when  the  mold  is  poured.  The  ribs  may  be 
drawn  separately  and  the  centre  square  last.  The  gate 
should  be  cut  opposite  the  ribs,  thus  reducing  to  a  mini- 
mum the  liability  of  cutting. 

When  the  bottoms  of  the  pockets  overhang  quite  a  dis- 
tance, it  is  advisable  to  put  double-end  chaplets  between 
the  core  and  the  cover  core.  This  takes  the  weight  of 
the  core  and  prevents  it  from  sagging  when  the  flask  is 
turned  over.  The  lifting  pressure  may  be  greater  than 
will  be  held  by  the  rods  that  are  placed  in  the  pockets.  In 
this  case,  a  plate  of  thin  cast  iron  may  be  placed  on  tht 
top  of  the  pocket  and  a  chaplet  run  through  the  cope 
to  bear  on  this  plate.  The  chaplet  should  be  wedged 
only  tight  enough  to  prevent  giving  but  not  so  as  to  en- 
danger cracking  the  green  sand.  Another  manner  of 
chapleting  these  pockets  will  be  to  use  a  double-end  chap- 
let  with  plates  on  both  sides  or  very  large  heads.  The 
chaplets  should  be  such  that  the  distance  between  the 
two  outer  faces  exactly  equals  the  thickness  of  the  plate. 


96 


FOUNDRY  PRACTICE 


The  plates  on  the  chaplets  are  necessary,  since  they  bear 
on  green  sand  and  small  heads  would  cut  through  with- 
out offering  much  resistance. 

Pulleys  having  a  face  of  any  desired  width  may  be 
made  by  use  of  a  pattern  ring  which  is  drawn  up  in 
molding  to  the  width  desired.  The  pattern  consists  of  a 
pattern  ring,  as  shown  in  Fig.  49,  the  arms  with  the  de- 
sired hubs,  and  the  core  prints.  Making  the  hub  sepa- 


Fig.  49- 

rate  from  the  arms  allows  putting  any  sized  hub  desired 
onto  the  one  set  of  arms. 

The  mold  is  made  by  the  method  of  bedding  in.  The 
drag  is  placed  on  the  bottom  board  and  rammed  with 
sand  nearly  to  the  height  that  the  pattern  ring  should 
be  placed.  Riddled  sand  is  put  in  to  a  height  such  that 
the  ring  will  bed  into  it.  The  ring  is  then  bedded  down 
to  such  a  distance  that  the  width  of  the  ring  plus  the 
distance  A,  Fig.  50,  will  equal  the  desired  width  of  face 


FOUNDRY  PRACTICE 


97 


plus  the  finish  on  the  pulley.  The  sand  is  then  rammed 
around  the  ring  nearly  to  its  top.  This  should  be  well 
vented  all  over  before  drawing  up  The  ring  is  then 
drawn  up  about  2  in.  by  placing  blocks  at  three  or  four 


i    * 

p 

1 

^ 

d 

fi® 

y 

xN^NXXXXXXXXXxX^XXXXXXXXXXXXX^XXXX 

LJ          LJ               LJ          LJ 

Fig.  50. 


points  about  the  rim  and  extending  above  the  ring  an 
even  height  on  each  one.  This  keeps  the  ring  even  when 
drawn  to  a  level  of  the  blocks  each  time.  In  ramming, 
the  sand  must  not  be  too  hard  about  the  ring  or  the 


LJ          LJ  LJ          LJ 

Fig.  51. 

iron  will  not  run  the  rim  full.     Usually  direct  the  ram- 
mer slightly  away  from  the  ring  rather  than  toward  it. 

The  arms  should  be  positioned  when  the  ring  has 
been  drawn  to  half  the  width  of  the  face  of  the  required 
pulley.  The  arms  are  bedded  in  and  the  parting  made 


FOUNDRY  PRACTICE 


from  the  centre  line  of  the  arms  having  the  sand  between 
them  come  to  a  "level  of  their  top,  giving  the  flask  as 
shown  in  Fig.  51.  This  is  for  the  purpose  of  not  having 
a  heavy  body  of  sand  hanging  below  the  anchor. 

Sand  is  riddled  over  the  parting  and  the  anchor 
placed  in  position.  The  anchor  as  shown  in  Fig.  52  has 
the  three  nuts  for  the  screw  eyes  which  are  for  lifting 
the  anchor.  These  screw  eyes  are  left  in  place  until 
after  the  cheek  is  rammed,  then  they  are  removed  and 
the  holes  covered  for  ramming  the  cope.  The  outer  cir- 


Fig. 52. 

cle  of  the  anchor  must  be  smaller  than  the  inside  of  the 
ring  to  allow  for  the  contraction  of  the  rim  when  cool- 
ing. Pieces  should  be  put  in  to  guide  the  anchor  back 
to  the  same  position  after  removing  from  the  mold. 
These  may  be  short  cones  or  square  pyramids.  They 
are  placed  in  two  or  three  places  between  the  arms  and 
extending  below  the  parting.  They  are  fastened  so  as 
to  ensure  remaining  firm  in  the  anchor.  These  pieces 
are  often  called  pulley  feet.  Around  the  edges  of  the 


FOUNDRY  PRACTICE 


99 


anchor,  nails  should  be  placed  to  extend  nearly  to  the 
pattern  and  firmly  anchor  the  sand  about  the  edges  and 
the  arms.  The  remainder  is  filled  in,  rammed  and  the 
pattern  drawn  until  the  parting  is  reached  at  the  top  of 
the  drag.  Two  small  gate  sticks  are  placed  on  the  hub 
for  admitting  the  metal.  The  flask  is  ready  for  forming 
the  parting  as  shown  in  Fig.  53,  and  for  placing  on  the 
cope  for  ramming. 

The  cope  is  rammed,  having  the  two  centre  gates,  a 
riser  on  the  rim,  and  a  vent  opening  from  the  cheek. 
The  cope  is  lifted  and  finished. 

The   vent   gutter   is   cut   around   the   outside   of   the 


Fig.  53- 

cheek  within  about  2  in.  of  the  ring  and  connecting  with 
the  vent  opening  in  the  cope.  Slant  vents  lead  to  the 
gutter  from  all  parts  of  the  cheek.  The  outside  is  vented 
and  led  to  the  parting  of  the  flask.  In  venting,  the  wire 
must  not  be  forced  deeper  than  the  pattern  ring,  because 
it  would  break  away  the  face  of  the  mold.  The  pat- 
tern ring  is  drawn  out  and  the  screw  eyes  are  replaced 
into  the  anchor  and  the  cheek  lifted  out.  The  arms 
may  then  be  drawn,  giving  the  mold  in  parts  as  shown 
in  Fig.  54.  These  may  be  finished  and  replaced,  then 
the  mold  closed. 


100 


FOUNDRY  PRACTICE 


A  pouring  basin  should  be  built  to  allow  pouring 
from  the  outside  of  the  flask.  The  riser  should  be 
built  to  the  height  of  the  basin  to  avoid  overflowing  onto 
the  flask. 


f 


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y 

y 

w. 

:;    !' 

y 

y 

.•;••'•'•"••"  'T  •',','••  /''•'.•••''•'•'  '•'•'''•'•'  '  <  •"  •''•  ^ 

a 

^\\NN 

ss^ssssssss^sssss^^ss 

\\,s 

s,\ 

Ni 

Fig.  54- 


The  methods  above  given  may  be  used  for  many 
forms  of  pulleys  and  sheave  wheels.  Double-arm  pul- 
leys may  be  made  in  this  manner  by  using  a  second  an- 


FOUNDRY   PRACTICE 


101 


chor  to  lift  the  cheek  from 
the  lower  set  of  arms.  The 
thickness  of  the  rim  may  be  increased 
by  placing  thin  strips  inside  of  the 
ring.  In  pulleys  having  wide  face,  it 
is  best  to  anchor  the  sand  in  the  out- 
side of  the  flask  so  that  it  may  be  lift- 
ed off.  The  face  of  the  pulley,  the  in- 
side of  the  rim,  and  the  bottom  of  the 
rim  may  be  finished  easily  when  thus 
removed. 

For  making  sheave  wheels  by  use 
of  the  pulley  ring  the  grooves  are 
made  in  core.  Sheaves  having  from  I 
to  3  grooves  are  made  without  using 
an  anchor  lift,  by  coping  out 
the  sand  above  the  arms  by  a 
cope  lift.  In  making  a  sheave,  the 
method  of  procedure  is  the  same  as 
that  of  a  pulley  until  the  cope  is  lifted 
off.  The  sand  on  the  outside  of  the 
pulley  ring  is  then  removed  to  a  depth 
equal  to  the  width  of  the  cores  which 
form  the  grooves.  The  centre  part  is 
finished  as  in  the  case  of  the  pulleys. 
The  cores  are  set  about  the  cheek  by 
use  of  strips  which  are  the  thickness 
of  the  metal  below  the  grooves.  The 
sand  is  filled  in  back  of  the  cores,  thus 
forming  the  outer  face  for  the  desired 
sheave.  The  strips  are  drawn  out 
and  the  mold  prepared  for  closing. 


Fig.  55- 


102 


FOUNDRY   PRACTICE 


Fijr.  56. 


FOUNDRY   PRACTICE  103 

Columns  are  cast  with  centre  cores  of  such  a  size 
that  the  thickness  of  metal  on  the  outside  is  that  de- 
sired. Fig.  55  shows  a  column  that  is  here  taken  to  ex- 
plain some  of  the  methods  for  making  such  forms  of 
castings. 

The  pattern  used  is  shown  in  Fig.  56.  It  is  a  halved 
pattern  longer  than  the  desired  casting  and  having  the 
brackets  loose.  The  drag  is  rammed  in  the  customary 
manner.  Facing  is  used  all  over  the  pattern  when  the 
length  and  thickness  of  metal  will  allow  without  cold- 
shotting  the  end  away  from  the  gate.  The  ramming 
must  be  even  throughout  its  length,  and  is  best  made 
much  harder  than  on  smaller  castings.  The  parting  is 
made  and  the  other  half  of  the  pattern  is  placed  in  posi- 
tion. Facing  should  be  put  on,  the  same  as  in  the  drag. 
It  should  be  tucked  beside  the  pattern  to  allow  the  gag- 
gers  to  be  placed  near  the  pattern.  The  cope  is  then 
placed  on  and  an  upset  placed  over  the  brackets  to  give 
sufficient  depth  of  sand  above  the  pattern.  The  gaggers 
are  set  in  the  cope.  They  should  be  long  enough  to 
reach  nearly  to  the  top  of  the  flask  and  have  a  heel  about 
6  in.  long.  The  gaggers  will  be  most  effective  when 
placed  in  the  division  having  the  heel  extending  parallel 
to  the  pattern  and  as  close  as  possible.  When  pointed 
toward  the  pattern  the  edge  is  liable  to  break  between 
the  gaggers.  It  is  only  necessary  to  ram  the  cope  one 
bar  back  of  the  collar.  The  gate  is  placed  in  this  divis- 
ion and  above  the  pattern.  A  riser  should  be  placed 
above  the  large  bracket.  When  the  column  has  metal 
so  thin  that  the  iron  is  liable  to  be  too  cold  when  it 
reaches  the  bracket,  it  is  preferable  to  have  a  gate  at  that 
end  and  pour  with  a  bull  ladle,  thus  supplying  hot  iron 
for  the  brackets.  The  cope  should  be  rammed  to  an 


104  FOUNDRY  PRACTICE 

even  hardness  the  same  as  that  of  the  drag  and  should 
be  well  vented.  The  bracket  must  be  anchored  as 
strongly  as  possible,  having  a  gagger  come  between  the 
bracket  and  the  beam  connection  to  prevent  the  metal 
from  breaking  through.  The  ramming  around  the 
bracket  should  be  lighter  than  on  the  main  body  of  the 
pattern.  The  pressure  of  the  metal  is  not  sufficient  to 
prevent  scabbing  or  blowing  as  in  the  other  parts.  The 
pattern  should  be  held  firmly  to  the  cope  by  wood  screws 
while  it  is  being  lifted  off. 

In  finishing  the  drag,  it  should  first  be  vented  by 
running  the  wire  under  the  pattern  from  the  sides  of 
the  flask  and  leading  these  vents  off  at  the  parting. 
Nails  should  be  put  in  the  corners  near  the  collars  and 


the  brackets.  The  joint  may  be  wet  with  the  swab,  then 
the  pattern  drawn.  The  brackets  still  remain  in  the 
drag.  A  large  nail  should  be  placed  in  each  corner  of 
the  bracket  and  two  placed  between  the  bracket  and 
beam  connection  to  prevent  breaking  through,  as  the 
metal  fills  one  before  entering  the  other.  The  brackets 
are  drawn  and  the  mold  slicked.  The  cores  shown  at 
A,  Fig.  57,  are  set  in  the  collars  and  those  at  B  are 
placed  in  the  beam  connection.  These  cores  must  be 
anchored  to  prevent  lifting,  due  to  the  buoyancy  of  the 
metal.  These  cores  may  be  held  by  nails  so  placed  as  to 


FOUNDRY  PRACTICE  105 

resist  an  upward  pressure.  The  end  stop-off  core  shown 
at  C  is  placed  at  the  outer  edge  of  the  collars.  This  core 
is  the  same  thickness  as  the  metal  of  the  desired  col- 
umn. The  chaplets  are  set  in  the  drag,  observing  the 
precautions  previously  given.  The  number  of  chaplets 
depends  upon  the  weight  and  length  of  the  centre  core. 
The  centre  core  is  placed  in  position  and  the  end  stop- 
off  cores  are  placed  on  the  top  side.  These  small  cores 
should  be  fastened  so  that  they  will  not  be  pressed 
forward  while  ramming  up  the  ends  or  be  washed  in 
by  the  iron.  The  gate  comes  through  the  end  stop-off, 
hence  it  must  be  cut  away  back  to  where  the  metal  enters 
from  the  cope  and  of  a  width  to  give  the  desired  area  of 
gate. 

The  cope  should  be  finished  similarly  to  the  drag  and 
the  small  cores  set  in  the  collars  and  the  beam  connection. 
The  edges  should  be  more  firmly  anchored  than  in  the 
drag,  so  as  to  ensure  holding  when  the  flask  is  closed. 

The  cope  chaplets  are  set  and  the  flask  may  be  closed. 

In  this  form  there  is  nothing  to  hold  the  metal  from 
forcing  the  end  cores  out,  hence  there  should  be  a  divis- 
ion of  the  flask  which  may  now  be  rammed  with  sand. 
The  vents  for  the  centre  cores  must  be  led  off  through 
the  portion  thus  rammed. 

The  pouring  basin  may  be  built  and  the  riser  raised 
to  the  level  with  it.  The  flask  is  clamped  and  chaplets 
properly  wedged,  thus  it  is  ready  to  receive  the  metal. 

The  strength  of  facing  and  the  amount  which  may  be 
used  is  entirely  dependent  upon  the  thickness  of  the  met- 
al and  the  length  of  the  column.  Generally,  when  the 
metal  is  I  in.  in  thickness,  facing  of  a  strength  of  from 
i — 10  to  i — 1 6  should  be  used  all  over  the  pattern, 
Small  columns  up  to  9  in.  in  diameter  having  metal  less 


io6  FOUNDRY   PRACTICE 

than   i    in.   in  thickness  should  not  be  covered  all   over 
with  facing  except  when  short. 

A  column  of  9-in.  diameter  and  >}4-in.  metal,  18  ft. 
long  may  be  made  with  facing  i — 16  covering  one-half 
its  length.  With  facing  stronger  or  covering  more  of  the 
pattern,  the  iron  is  so  cold  before  reaching  to  opposite 
end  that  it  causes  cold-shots  or  it  will  not  run  full. 

The  manner  of  gating  a  column  is  dependent  upon 
the  size  of  the  column.  For  small  and  thin  columns,  a 
single  gate  at  the  end  supplies  the  metal  fast  enough  and 
enables  forcing  in  case  the  metal  is  somewhat  cold.  In 
larger  sizes,  as  from  10  in.  up,  or  9  in.  having  thick  met- 
al, a  gate  on  each  side  is  more  desirable.  The  metal  may 
be  led  in  by  the  end  core  or  at  the  side  by  a  runner  and 
several  gates. 

In  making  cast  gears,  it  is  very  important  to  main- 
tain the  exact  form  of  the  pattern  and  form  all  the  teeth 
perfectly.  The  teeth  are  the  most  important  part  of  such 
a  casting,  for  if  some  are  out  of  shape  it  will  not  run 
with  the  gear  meshing  into  it,  hence  the  casting  can  not 
be  used. 

The  sand  must  be  rammed  into  the  teeth  uniformly, 
and  that  as  soft  as  will  resist  the  pressure  of  the  metal. 
In  small  gears  it  can  be  done  best  by  riddling  the  sand 
outside  and  throwing  it  into  the  teeth  until  all  are  cov- 
ered, then  ramming  up  the  backing  moderately  hard.  In 
large  gears,  the  sand  should  be  nailed  or  rodded  while 
being  rammed  and  care  should  be  used  to  ram  the  teeth 
to  an  even  hardness. 

When  a  gear  is  so  small  that  facing  can  not  be  used, 
mix  new  sand  with  the  old  in  a  proportion  of  i  part 
new  sand  to  3  parts  old  sand  and  use  it  for  the  fac- 
ing. In  all  other  gears  use  facing  varying  in  strength 


FOUNDRY   PRACTICE  107 

according  to  size.  Generally  use  facing  of  strength  of 
i  part  sea  coal  to  12  parts  sand.  Never  use  plumbago 
or  blacking  on  the  teeth  unless  they  are  of  large  enough 
size  to  smooth  it  on  with  a  brush  or  slick.  The  loose 
(lust  only  roughens  the  casting  and  causes  a  dirty,  UP 
even  surface. 

The  teeth  of  a  gear  can  not  be  patched  with  tools  as 
can  corners  and  surfaces  of  a  common  mold.     The  form 


Fig.  58. 

of  the  tooth  must  be  true,  hence  it  is  important  that  the 
pattern  draw  out  well  leaving  the  teeth  without  tearing. 
Some  patterns  have  the  teeth  dovetailed  into  the  body, 
then  if  any  tooth  does  not  leave  the  mold  well  it  may 
be  pressed  down  and  drawn  out  separately.  With  other 
patterns,  in  case  of  patching  being  necessary  the  pat- 
tern must  be  replaced  and  the  tooth  reformed. 

The  gate  must  always  be  placed  upon  the  centre  of 


io8  FOUNDRY  PRACTICE 

a  gear  as  the  teeth  would  be  very  liable  to  wash  if  the 
metal  entered  the  mold  from  the  rim. 

The  method  of  procedure  in  making  a  gear  from  a 
solid  pattern  may  be  shown  in  making  a  mold  for  the 
bevel  gear  shown  in  Fig.  58.  The  parting  comes  at  the 
top  or  outer  diameter  of  the  teeth  and  at  the  bottom  of 
the  hub  at  the  short  side'  of  the  arms.  If  a  special  follow- 
board  or  match  is  made  for  the  pattern,  the  drag  may 
be  placed  and  rammed.  In  other  cases,  a  match  must 
be  made  on  the  cope.  The  cope  is  laid  on  a  sand  bed 
with  the  pins  upward.  Sand  is  filled  in  and  rammed  to  a 
height  that  brings  the  parting  line  of  the  teeth  even  with 
that  of  the  flask  when  the  pattern  is  in  position.  The 
sand  is  rammed  around  the  pattern  until  the  level  of  the 
parting  is  reached.  The  parting  between  the  arms  is 
more  easily  made  from  this  side  than  after  the  pattern 
is  reversed ;  so  this  portion  of  the  parting  is  made,  and 
parting  sand  put  upon  it.  The  drag  is  placed  upon  the 
cope,  facing  sand  is  thrown  into  the  teeth  until  they  are 
well  covered,  sand  is  riddled  over  this,  and  the  remain- 
der is  filled  and  rammed.  The  drag  is  vented,  care  being 
used  not  to  strike  the  teeth  of  the  pattern.  The  whole 
is  turned  over  and  the  cope  lifted  while  the  pattern  is 
held  into  the  drag.  The  parting  at  the  outside  of  the 
pattern  is  first  made  and  the  sand  removed  from  the  cen- 
tre down  to  the  pattern.  The  pattern  and  adjacent  sand 
are  marked  at  some  point  by  which  to  replace  the  pattern 
after  it  has  been  removed.  The  pattern  is  rapped  to 
loosen  the  sand  in  the  teeth,  then  drawn,  carrying  with  it 
the  sand  above  the  parting  previously  made.  The  pat- 
tern is  brushed  clean  and  replaced,  which  completes  the 
parting  of  the  drag.  Facing  is  riddled  over  the  face  of 
the  drag  and  the  cope  is  replaced.  Soldiers  are  placed  to 


FOUNDRY   PRACTICE  109 

anchor  the  sand  between  the  arms.  These  should  ex- 
tend to  the  top  of  the  cope  to  ensure  sufficient  strength  to 
hold  the  sand  firmly  when  the  pattern  has  been  removed. 
The  gate  stick  is  placed  on  the  hub  beside  the  core  print. 
Facing  is  filled  in  to  cover  the  pattern  and  rammed  be- 
tween the  arms  with  a  hand  rammer  or  rod  that  will 
tighten  the  sand  evenly  around  the  soldiers.  The  re- 
mainder of  the  cope  is  filled  and  rammed,  care  being- 
used  to  ram  around  the  soldiers  without  striking  them. 
The  cope  is  well  vented  and  the  gate  stick  removed  with- 
out reaming  or  enlarging  the  hole,  so  that  it  may  be  re- 
placed after  the  flask  is  closed.  A  wood  screw  or  draw- 
spike  is  placed  in  the  hub  through  the  gate.  This  is  held 
and  slightly  rapped  as  the  cope  is  lifted  off.  The  rap- 
ping frees  the  teeth  and  the  pattern  is  held  firmly  in  the 
cope  by  lifting  on  the  screw.  The  sand  around  the  pat- 
tern and  between  the  arms  is  patched  and  nailed  where 
necessary.  In  large  patterns  the  sand  should  be  nailed 
before  drawing  the  pattern,  to  help  hold  the  sand  from 
loosening  or  dropping  while  closing  the  mold.  The  sand 
at  the  edges  of  the  pattern  is  moistened  with  the  swab 
and  the  pattern  drawn.  In  case  any  of  the  teeth  were' 
torn  or  damaged  when  the  cope  was  lifted,  the  pattern 
should  be  replaced  on  the  drag  and  the  tooth  reformed  by 
ramming  in  sand  with  a  small  rod  or  nail.  The  pattern, 
then  drawn,  should  give  a  perfect  set  of  teeth  as  de- 
sired. Blacking  may  be  put  upon  the  cope  and  slicked, 
but  it  is  preferable  to  leave  the  drag  without  blackening. 
The  centre  core  is  vented  off  at  the  bottom  and  has  its 
top  vent  closed  with  sand  so  the  iron  cannot  flow  into  it. 
The  flask  is  closed  and  the  gate  stick  replaced.  A  basin 
is  built  about  it  as  shown  in  Fig.  47,  so  that  the  metal 
will  not  be  poured  directly  into  the  gate,  giving  the  addi- 
tional strain  due  to  the  metal  dropping  from  the  ladle. 


CHAPTER   III 

Cores  are  bodies  of  sand  in  the  mold  for  forming  in- 
terior openings  or  holes  in  the  casting.  They  may  be 
made  of  green  sand,  dry  sand  or  loam.  Some  patterns 
are  of  such  form  that  the  core  is  formed  by  the  pattern. 
Generally  the  core  is  made  separate  from  the  mold  and 
placed  into  it.  When  made  in  green  sand  it  maintains 
the  shape  more  accurately  than  dry  sand,  as  the  core  is 
often  distorted  in  drying.  It  requires  more  skill  and 
time  to  form  green  sand  cores  than  dry  sand,  hence  the 
dry  sand  is  used  when  the  core  is  not  simple  or  easily 
made  in  green  sand. 

Dry  sand  cores  may  be  made  in  a  great  variety  of 
shapes  to  suit  any  case.  They  are  made  strong  enough 
to  resist  the  pressure  of  the  metal,  and  may  be  anchored 
so  as  to  be  surrounded  by  metal,  except  an  opening 
through  which  the  gases  escape.  The  use  of  cores  great- 
ly simplifies  molding  in  many  cases.  They  may  be  used 
to  stop  off  portions  of  the  pattern,  to  prevent  the  neces- 
sity of  many  parts  to  the  flask,  to  form  irregularities  and 
pockets  that  would  be  difficult  to  make  with  the  pattern, 
and  to  form  parts  of  molds  instead  of  using  a  pattern,  us 
in  pit  molding. 

A  dry  sand  core  is  any  form  made  in  sand  mixtures, 
dried  until  hard  to  allow  handling,  and  used  to  form 
part  of  a  mold.  These  cores  may  be  made  in  any  form 


FOUNDRY  PRACTICE  in 

from  the  plain  to  the  very  intricate  and  irregular  cores 
required  in  some  castings.  When  properly  dried,  the 
core  becomes  hard  so  it  may  be  handled,  and  may  be 
anchored  by  use  of  chaplets  when  necessary.  The  bind- 
er used  in  the  mixture  holds  the  sand  together  so  that 
shapes  may  be  easily  made  which  would  be  very  difficult 
to  form  in  green  sand.  Dry  sand  cores  may  be  made 
strong  enough  to  support  the  sand  of  portions  of  a  mold 
or  to  resist  great  pressures  from  the  metal. 

The  proper  venting  of  cores  is  a  necessity.  All  core 
mixtures  have  a  binder  which  holds  the  sand  together 
when  dried.  This  binder  burns  out  when  in  contact  with 
the  molten  iron,  giving  off  gases  which  greatly  increases 
that  in  the  new  sand  used  in  the  core.  This  formation- 
of  gas  must  have  free  relief  within  the.  core  to  prevent  its 
forcing  its  escape  through  the  metal.  All  mixtures 
for  cores  must  be  sufficiently  open  to  give  free  passage 
for  the  gases. 

Cores  having  metal"  against  but  one  face  will  not  re- 
quire any  special  vents.  Small  round  cores  require  a 
vent  through  the  centre.  This  should  extend  throughout 
its  length.  Cores  having  one  face  not  covered  by  the 
metal  may  be  vented  to  this  face  by  a  vent  wire  to  give 
the  necessary  relief  to  the  gases. 

When  the  core  is  large  or  not  easily  vented,  coke, 
cinders,  stones,  or  any  very  open  material  is  placed  in 
the  core  to  collect  the  gases,  which  are  led  off  by  an 
opening  to  the  outside.  Straight  cores  may  be  vented  by 
rods  placed  in  the  box  when  ramming  the  core.  Crooked 
cores  are  vented  by  many  methods.  When  large  enough 
to  use  coke  without  weakening  the  core,  the  vent  may  be 
led  out  by  placing  coke  through  the  centre  of  the  crook- 
ed part  to  lead  to  the  vent  opening.  Small  crooked  cores 


"H2  FOUNDRY  PRACTICE 

may  be  vented  in  many  ways.  A  roll  of  paraffine  laid 
through  the  core  when  rammed  will  melt  and  run  out 
when  the  core  is  dried,  giving  the  desired  vent.  Straight 
vents  may  be  made  to  the  bent  portion  of  a  core,  and 
after  drying  these  are  connected  by  cutting  away  the 
core  and  laying  in  a  string  through  one  vent  and  extend- 
ing into  the  other,  then  covering  with  new  molding  sand 
or  core  mixture  to  reform  the  shape.  The  desired  vent 
is  left  when  the  string  is  drawn  out. 

Core  sand  will  admit  of  hard  ramming  without  caus- 
ing trouble  when  used.  When  rammed  hard,  the  core 
will  be  stronger.  The  only  precaution  is  to  have  the  sand 
left  sufficiently  open  to  give  free  vent.  All  ramming 
must  be  done  with  the  pein  rammer  until  the  last  surface 
is  reached,  when  it  is  butted  off.  If  the  butt  is  used  be- 
tween the  layers  while  filling  a  box,  the  surface  made 
will  not  unite  with  the  sand  rammed  on  top,  which 
makes  a  weak  place  in  the  core.  If  the  sand  is  too  wet,  it 
should  not  be  rammed  so  hard,  for  the  pores  close  easier 
and  form  a  solid  cake  which  will  blow  when  used  in  the 
mold. 

Cores  may  be  greatly  strengthened  by  putting  wires 
and  rods  into  them.  The  sand  adheres  to  the  rods  so 
closely  that  it  cannot  be  pulled  out  even  tor  a  short  dis- 
tance. This  strengthens  the  core  far  more  than  the  sim- 
ple bending  of  the  rod,  because  it  causes  a  tension  in  the 
rod,  due  to  a  tendency  to  elongate  in  an  arc  of  a  circle 
whose  centre  is  at  the  surface  of  the  core.  This  action 
is  effective  only  to  the  amount  necessary  to  crush  the  core 
at  that  centre.  Small  cores  needing  but  little  strength 
do  not  require  rods.  The  strength  due  to  the  dry  sand  is 
sufficient  where  there  is  not  much  pressure  or  weight  to 
be  borne. 


FOUNDRY  PRACTICE  113 

The  rods  necessary  for  a  core  depend  upon  the 
weight  of  the  core  and  the  strength  it  must  have.  Many 
cores  are  of  such  size  or  shape  that  they  would  not  bear 
their  own  weight  without  rodding.  Small  and  thin  cores 
may  be  sufficiently  rodded  by  heavy  wire.  All  oil  cores, 
except  very  small  ones,  should  have  rods  to  hold  them 
to  shape  while  green  and  to  give  extra  strength  when 
dried.  The  oil  will  adhere  to  the  rod  so  that  it  becomes 
so  firmly  fixed  that  the  core  will  break  a  wire  before 
loosening  from  it.  Larger  cores  are  rodded  in  all  direc- 
tions so  as  to  tie  the  whole  together  firmly.  The  rods 
are  bent  to  conform  to  the  desired  shape. 

Many  cores  require  to  be  hung  in  the  cope.  These 
must  have  hooks  or  loops  in  them  for  their  support. 
Other  cores  require  the  loop  for  handling  or  setting  them 
into  the  mold.  The  loop  is  made  of  wire  or  rods  of  the 
necessary  strength  and  is  placed  in  the  desired  position 
:n  the  core.  Except  when  the  core  is  small,  the  loop  is 
anchored  in  the  core  by  cross  rods  so  placed  as  to  brace 
the  entire  core  from  the  loop.  This  gives  strength  to  the 
core  and  makes  the  loop  capable  of  bearing  the  weight. 

Large,  heavy  cores  can  not  be  safely  rodded  by  loose, 
separate  rods,  as  it  does  not  give  the  sufficient  strength. 
Special  anchors,  bars,  or  core  irons  are  used  in  these 
cases.  These  core  irons  may  be  of  cast  iron,  of  wrought 
iron  welded  together,  or  may  have  cast  iron  bodies  with 
wrought  iron  parts.  These  are  so  shaped  as  to  carry  the 
entire  core  firmly  from  the  core  iron.  The  hooks  or  nuts 
for  screw  eyes  are  made  solid  to  the  core  iron  for  hand- 
ling. When  the  core  has  a  large  body  part,  loose  bars 
and  rods  are  used  to  bind  the  whole  to  the  core  iron.  In 
many  cases,  the  iron  in  it  weighs  more  than  the  sand. 

Many  cores  are  made  in  two  or  more  parts  and  are 


n4  FOUNDRY  PRACTICE 

pasted  together  after  drying.  This  is  done  in  order  to 
give  a  form  to  the  core  that  will  hold  its  shape  before 
drying.  Large  round  cores  will  sag  and  deform  while 
green  if  made  full,  supported  on  a  side.  When  made  in 
halves  the  support  comes  upon  the  flat  side,  giving  suf- 
ficient strength  to  maintain  its  shape.  The  making  of 
cores  in  halves  greatly  simplifies  the  boxes  used  and 
gives  the  largest  face  outward  to  work  from  in  making 
the  core. 

The  halves  are  pasted  together  after  drying,  to  form 
the  complete  core.  The  paste  used  must  be  sufficiently 
strong  to  hold  the  core  when  handled,  when  set  in  the 
mold  and  when  the  mold  is  poured.  Wheat  or  rye  flour 
wet  with  water  to  an  even  mixture  forms  a  strong  paste 
for  this  purpose.  Graham  flour,  buckwheat  flour,  and 
fine  meal  each  makes  a  paste  that  may  be  smoother  but 
not  so  strong  as  wheat  flour. 

In  pasting  a  core  the  halves  must  come  to  a  close 
bearing  all  over  the  surface  of  the  joint.  When  the  joint 
surface  is  warped  or  irregular,  the  halves  may  be  rubbed 
together  until  a  good  bearing  is  obtained.  When  large 
or  very  irregular,  the  high  places  may  be  filed  off  or 
rubbed  down  with  a  brick.  In  some  cases  the  halves  are 
slightly  thick,  causing  the  core  to  be  elliptical  when  past- 
ed. Therefore  a  core  should  be  measured  with  a  caliper, 
and,  when  too  thick,  the  joint  should  be  rubbed  down  un- 
til the  proper  thickness  is  obtained. 

The  sand  and  dust  on  the  joint  must  be  brushed  off 
before  putting  on  the  paste,  as  the  dust  takes  up  the  paste 
and  prevents  the  solid  joint  desired.  The  paste  should 
be  spread  over  the  portion  forming  the  joint;  the  core  is 
then  put  together  and  rubbed  slightly,  with  pressure  to 
give  close  union  to  the  parts. 


FOUNDRY  PRACTICE  115 

In  pasted  cores,  the  vent  is  taken  off  at  the  joint  by 
cutting  gutters  in  the  joint  surface  and  leading  off 
through  the  print  portion.  These  gutters  must  be  kept 
open  when  the  core  is  pasted.  Sometimes  it  is  advisable 
to  lay  into  the  gutter  a  rod,  a  string,  or  anything  that 
may  be  drawn  out  after  pasting. 

The  paste  must  be  dried  in  order  to  give  it  strength. 
If  pasted  while  hot,  the  core  will  dry  the  paste.  When 
pasted  cold,  the  core  should  be  put  in  the  oven  until 
dried. 

If  the  core  is  properly  pasted  and  dried,  the  joint  will 
be  as  strong  as  any  part  of  the  core  outside  of  the  rods 
or  anchors. 

All  cores  are  baked,  or  dried,  to  drive  off  the  moisture 
and  harden  the  core.  If  a  core  is  heated  too  much  or 
left  in  the  oven  after  it  is  dry,  the  binder  burns  out,  leav- 
ing the  soft  burnt  sand  which  crumbles  and  can  not  be 
used.  When  a  core  is  dry  it  will  give  a  clear  ring  when 
tapped  with  a  stick  or  hammer.  A  convenient  tool  for 
sounding  a  core  is  the  handle  of  a  trowel.  If  the  core 
is  only  partly  dry  the  ring  will  be  deadened. 

Cores  may  also  be  tested  for  dryness  by  the  odor. 
When  green  the  flour,  or  binder,  gives  an  odor  similar  to 
sour  dough.  When  dry,  no  steam  nor  odor  of  green 
binder  can  be  detected. 

The  ovens  for  drying  cores  are  of  various  kinds,  chief- 
ly using  direct  heat  although  some  have  indirect  heat. 
The  indirect  heat  process  is  where  the  fire  is  in  a  separate 
chamber  about  the  oven  where  the  cores  are  dried.  The 
direct  heat  process  is  to  have  the  fire  so  placed  that  the 
heat  and  smoke  pass  directly  through  the  oven  into  the 
chimney. 

By  indirect  heating,  the  intensity  of  the  heat  is  more 


ii6  FOUNDRY   PRACTICE 

nearly  even  throughout  the  oven.  By  direct,  the  upper 
part  is  always  much  hotter  than  the  lower  part.  By  direct 
heating,  the  chimney  flue  opens  from  the  lower  part  of 


Fig,  59- 


the  oven  at  the  end  opposite  the  fire.  This  draws  the 
cooler  air  from  the  bottom,  which  must  be  replaced  by 
the  hotter  air  from  the  upper  part  or  from  the  fire ;  thus 


FOUNDRY   PRACTICE 


117 


it  distributes  the  heat  more  evenly  and  reduces  the  loss  cf 
heat  passing  into  the  chimney. 

The   ovens    for    small    cores    are   fitted    with    shelves 


Fig.  60. 

upon  which  the  plates  of  cores  may  be  placed.     These  are 
so  arranged  as  to  be  convenient  and  accessible  while  the 


o 


Fig.  61. 

oven  is  hot.  A  convenient  form  of  oven  for  small  cores 
is  shown  in  Fig.  59.  In  this  oven  the  shelves  are  of  the 
form  of  a  semicircle  hung  at  its  centre.  A  door  is  fitted 


ii8  FOUNDRY  PRACTICE 

to  each   side,   thus  closing   the   oven    when   the   shelf   is 
swung  out  or  in. 

The  common  forms  of  core  ovens  have  the  shelves 
fixed  within  the  oven.  The  cores  are  placed  upon  the 
shelves  through  a  door  that  opens  in  front  of  the  shelves, 


Fig.  62. 


or  the  oven  is  so  arranged  that  the  coremaker  may  go 
inside  the  oven  to  the  shelves  arranged  about  in  it. 
The  ovens  have  the  coke  fire  at  one  end  while  the 
gases  are  drawn  off  near  the  bottom  at  the  opposite 


FOUNDRY  PRACTICE  119 

end.  This  arrangement  distributes  the  heat  as  evenly 
as  possible  but  great  variation  is  noted  at  various 
points  of  the  oven.  The  shelves  at  the  top  nearest  the 
fire  are  very  hot,  while  the  ones  that  are  low  at  the  oppo- 
site end  are  not  hot  enough  to  dry  a  core.  This  distribu- 
tion of  heat  is  often  of  advantage,  as  those  cores  which 
must  be  dried  quickly  or  slightly  burned,  as  oil  cores, 
may  be  placed  on  the  hottest  shelves,  while  other  cores 
may  be  best  dried  in  cooler  portions  of  the  oven.  Cores 
that  are  replaced  in  the  oven  for  drying  the  blacking  or 
the  paste  may  best  be  placed  in  the  coolest  parts  of  the 
oven. 

Fig.  60  shows  an  elevation  and  a  sectional  view  of 
an  oven  for  small  cores.  Fig.  61  gives  detail  of  the  same, 
showing  its  operation.  The  shelves  for  the  cores  are 
mounted  on  wheels  at  the  back  and  are  carried  at  the 
front  by  the  trolley  while  the  shelf  is  drawn  out.  Each 
shelf  has  its  door  at  front  and  at  back  so  that  the  oven 
is  closed  when  the  shelf  is  out  or  in.  Any  one  may  be 
drawn  out  by  hooking  the  trolley  to  the  handle,  as  in  the 
case  of  the  one  in  Fig.  61.  The  whole  number  may  be 
drawn  at  once  if  so  desired. 

A  form  of  oven  used  extensively  in  shops  making 
a  special  line  of  castings  is  one  having  a  core-truck  with 
shelves  fitted  for  the  special  cores  used.  The  truck  is 
drawn  out  of  the  oven  while  it  is  loaded  or  unloaded,  and 
is  replaced  in  the  oven  while  drying  the  cores.  A  form 
of  such  a  truck  is  shown  in  Fig.  62.  The  oven  for  this 
purpose  has  its  interior  dimensions  to  suit  the  size  of 
truck  and  its  front  end  is  fitted  with  some  form  of  door 
that  may  be  opened  for  removing  the  truck.  The  fire  is 
made  below  the  floor  line  at  the  back  end  of  the  oven  and 
the  gases  drawn  off  at  the  front  end  near  the  bottom  of 


120 


FOUNDRY  PRACTICE 


the  oven.  A  simple  form  of  truck,  or  core  car,  is  shown 
in  Fig.  63.  This  is  suited  to  large  cores  of  any  form. 
It  is  of  advantage,  in  jobbing  shops  having  heavy  cast- 
ings, because  the  cores  there  used  vary  greatly  in  size 
and  form.  These  may  be  decked  by  placing  rests  on  the 
platform  and  laying  bars  across. 

The  mixture  for  a  core  may  vary  greatly  to  suit  par- 
ticular conditions  and  different  sands.  The  amount  of 
binder  necessary  is  that  which  will  form  a  hard  core 
when  dry  and  which  will  not  be  too  close,  nor  burn  out, 


\£J_ 


Fig.  63. 

allowing  the  metal  to  enter  into  the  core  forming  rough- 
ness on  the  casting. 

The  mixture  given  in  Receipt  No.  I  is  well  adapted 
to  small  cores  made  on  the  bench.  With  some  sands 
this  percentage  may  be  increased.  With  large  cores,  the 
percentage  may  be  reduced  to  that  of  I  part  flour  to  12 
parts  sharp  sand. 

The  core  may  be  strengthened  in  heavy  work  by 
mixing  a  percentage  of  new  molding  sand  with  the 
sharp  sand.  The  mixture  given  in  Receipt  IV  gives  a 


FOUNDRY  PRACTICE  121 

strong  core  for  large  work,  as  arm  cores  for  fly  wheels, 
etc. 

When  a  core  is  nearly  surrounded  by  metal,  it  is  nec- 
essary to  have  a  strong  core  with  as  little  enclosed  gas  as 
possible.  Receipt  II  forms  a  core  which  is  very  strong 
and  which  may  be  easily  vented  since  it  is  nearly  an  oil 
core.  This  mixture  while  green  will  not  have  much , 
strength  so  that  it  may  be  difficult  to  dry  without  its  los- 
ing the  form  desired.  By  adding  a  small  percentage  of 
flour,  the  green  core  has  more  strength  and  has  as  much 
strength  when  dry. 

Receipt  III  will  give  a  hard  oil  core  which  has  great 
strength  for  its  size  and  will  not  blow  when  the  metal 
covers  the  greater  percentage  of  it.  This  is  of  greatest 
value  in  making  thin  split  cores.  The  core  should  be 
slightly  burned  after  drying,  to  give  an  open  texture 
without  injuring  its  strength. 

The  mixture  given  in  Receipt  V  is  for  making  cores 
by  the  machine.  The  proportions  may  be  varied  to  give 
the  best  core  with  the  easiest  operation  of  the  machine. 
If  the  sand  is  too  wet  or  has  too  much  flour,  it  will  stick 
to  the  tube,  thus  clogging  the  machine.  If  .too  dry,  the 
machine  will  not  compress  the  sand  sufficiently  to  give  a 
strong  core.  These  cores  are  improved  by  burning  slight- 
ly while  drying. 

Receipt  I. — 6  parts  fine  sharp  sand,  i  part  flour,  wet  with 
water.  Vary  the  above,  to  suit  conditions,  to  12  parts 
sand  to  i  part  flour. 

Receipt  II. — 2  parts  fine  sharp  sand,  i   part  new  mold- 
ing sand.     To  75  parts  of  mixture  add  i  part  of  lin- 
seed oil  or  core  compound. 
Receipt  III. — Add  oil  to  the  sharp  sand  until  it  becomes 


122  FOUNDRY   PRACTICE 

saturated,  or  will  show  slightly  on  the  finger-nail  when 

pressed  into  the  sand. 
Receipt  IV. — 3  parts  of  sharp  sand,  i  part  new  molding 

sand,  i  part  flour  to  8  parts  of  the  mixture.    Wet  with 

water. 
Receipt  V. — 10  parts  of  medium  grade  sharp  sand,  i  part 

flour.     To  75  parts  of  mixture  add  i  part  linseed  oil. 

Moisten  with  water  until  the  whole  adheres. 

The  face  of  the  core  which  is  to  be  covered  with  iron 
is  coated  with  blacking  to  give  a  smooth  face  and  prevent 
fusion  with  the  sand. 


Fig.  64. 

The  mixtures  of  blacking  for  dry  sand  molds  give  a 
very  good  mixture  for  large  cores.  Cheaper  mixtures 
give  good  results  on  small  cores.  The  simplest  blacking 
is  the  prepared  core  blacking  or  black  lead  mixed  with 
water  to'  the  desired  thickness.  A  better  mixture  for 
light  cores  may  be  made  by  use  of  the  following  receipt : 
Mix  6  parts  charcoal  blacking  and  i  part  graphite.  Wet 
with  molasses  water  or  sour  beer. 

Hay  or  straw  is  twisted  into  ropes  in  order  to  form 
an  open  band  which  may  be  placed  where  it  gives 
strength  in  holding  the  sand,  besides  providing  a  free 


FOUNDRY  PRACTICE  123 

escape  for  the  gases.  It  is  used  chiefly  in  loam  work 
or  in  cores  where  the  core  barrel  is  used.  It  is  some- 
times used  in  molds  to  provide  a  vent  passage  from 
parts  of  the  mold. 

The  rope  is  made  by  twisting  by  hand  or  by  the  use 
of  a  hay-rope  twisting  machine.  Fig.  64  shows  a  ma- 
chine for  twisting  hay  rope  and  winding  the  rope  upon  a 
reel  for  convenience  in  handling. 

Long  round  cores  are  often  made  upon  a  core  barrel 
to  give  them  strength  and  to  lessen  the  amount  of  core 
sand  necessary  to  make  the  core.  The  barrel  is  a  pipe  of 
wrought  or  cast  iron  having  holes  through  its  surface  to 
allow  the  free  escape  of  the  gases  from  the  outside  to  the 
inside  of  the  barrel.  When  made  of  cast  iron,  the  outer 
face  has  projections  and  unevenness  for  holding  the  core 
sand  to  the  barrel.  Wrought  iron  barrels  may  be  the 
plain  pipe  with  vent  holes  drilled  through  at  frequent  in- 
tervals. 

The  core  barrel  is  used  for  making  the  centre  core 
for  columns,  pipes,  cylinders,  and  round  cores  of  that 
type.  The  core  made  on  the  core  barrel  is  much  lighter 
and  easier  to  handle  than  a  solid  sand  core.  The  barrel 
gives  the  core  greater  strength  than  the  rods,  especiall) 
in  cores  of  small  diameter.  The  amount  of  core  mixture 
used  to  make  the  core  will  be  that  necessary  to  form  a 
shell  over  the  barrel,  while  the  other  core  must  be  solid. 
The  saving  of  core  mixture  is  often  worthy  of  consider- 
ation. 

In  order  to  form  a  core  on  a  core  barrel,  the  barrel  is 
wrapped  with  hay  or  straw  rope,  then  covered  with  loam 
or  core  mixture  to  give  the  desired  diameter.  The  barrel 
is  placed  upon  supports  at  each  end  and  fitted  with  a 
crank  so  that  it  may  be  rotated.  This  mechanism  with 


124 


FOUNDRY  PRACTICE 


the  strike  or  sweep  for  forming  the  face  of  the  core  is 
called  a  core  lathe.  The  end  supports  may  be  a  frame 
having  a  notch  in  the  upper  side  for  holding  the  barrel  or 
centre  shaft  which  supports  the  barrel.  The  frame  ex- 
tends horizontally  to  support  the  sweep.  The  barrel  is 
placed  upon  the  supports  and  rotated  by  the  crank,  while 
the  core  maker  guides  the  hay  rope  onto  it  until  the  de- 
sired length  is  covered.  The  surface  is  then  covered  with 
the  core  sand  and  compressed  to  give  the  necessary 
strength.  The  sweep  is  placed  upon  the  supports  and 
the  surface  swept  up  by  rotating  the  barrel.  The  sweep 
is  moved  toward  the  axis  until  the  desired  diameter  of 


U 


u 


Fig.  65. 

core  is  formed,  when  the  surface  is  slicked  ready  for  dry- 
ing. 

The  procedure  in  making  cores  varies  to  quite  an  ex- 
tent in  particular  cases.  The  general  principles  always 
apply  and  the  variations  are  mainly  in  rodding,  venting, 
and  mixture  of  sand  best  suited  to  the  special  core  de- 
sired. It  being  impossible  to  give  examples  and  explana- 
tion to  cover  every  case,  a  few  examples  are  given  to  il- 
lustrate the  principal  methods  of  making  cores. 

All  small  cores  that  do  not  require  rodding  are  made 
by  ramming  the  box  full  of  the  core  mixture  and  venting 


FOUNDRY   PRACTICE  125 

toward  the  print  side  of  the  core.  It  is  then  ready  to  put 
on  the  plate  for  drying. 

Fig.  65  shows  a  box  for  making  a  round  core.  The 
method  of  making  such  a  core  is  here  given.  The  two 
parts  of  the  box  are  clamped  together  and  placed  on 
end  upon  a  smooth  board  or  plate.  Some  core  sand  is 
placed  in  the  box,  then  the  vent  wire  is  pressed  into  the 
centre.  The  sand  is  rammed  around  the  vent  wire  with 
any  convenient  rod.  This  form  of  core  will  stand  to 
be  rammed  quite  hard.  The  ramming  is  continued  while 
the  sand  is  added  in  small  amounts  until  the  box  is  full. 
The  top  is  slicked  even  with  the  box  and  the  vent  wire 
withdrawn.  The  box  is  inverted  and  the  lower  end 
slicked  even  with  the  box  if  it  were  not  so  left  by  the 
piece  it  rested  upon.  The  clamps  are  removed  from  the 
box.  The  core  is  loosened  by  rapping  the  box  on  the 
sides. 

Half  of  the  box  is  lifted  off  from  the  core,  leaving 
it  in  the  lower  half.  This  is  turned  out  upon  the  plate 
by  the  following  method.  Place  the  part  containing  the 
core  on  the  plate.  With  the  fingers  of  both  hands  gently 
resting  on  the  core,  raise  the  box  with  the  thumbs  so 
that  it  turns  over  until  the  fingers  nearly  touch  the  plate. 
Gradually  withdraw  the  fingers  allowing  the  core  to  slide 
down  to  the  plate  evenly  and  gently.  The  core  may  be 
moved  by  placing  a  straight  side  of  the  box  against  it 
and  moving  the  box  until  the  core  is  in  the  desired  place. 

The  object  of  placing  the  vent  wire  before  ramming 
is  to  keep  it  in  the  centre  of  the  core.  When  the  core  is 
short,  it  may  be  quicker  to  ram  the  box  full,  then  press 
the  vent  wire  through,  using  care  to  keep  it  in  the  centre. 
When  the  core  is  long  and  must  bear  a  pressure  it  should 
have  a  rod  put  in  while  ramming.  Many  core  makers 


126 


FOUNDRY   PRACTICE 


press  the  rod  in  after  ramming  the  core  by  running  the 
vent  wire  through  first.  This  is  a  very  poor  plan,  as 
the  sand  may  be  loose  around  the  rod,  so  that  it  does 
not  strengthen  the  core,  or  it  may  close  the  vent,  causing 
trouble  in  that  way.  In  order  that  a  rod  should  strength- 
en a  core,  it  must  be  solid  into  the  sand  as  a  part  of  it. 


Fig.  66. 

Many  cores  are  made  in  a  skeleton  box  with  a  strike 
or  former.  This  form  of  box  is  very  cheap  to  make 
and  a  core  may  be  readily  made  in  it.  Fig.  66  shows 
such  a  box  with  its  strike.  This  makes  one-half  of  the 
core,  which  when  pasted  forms  the  core  shown  in  Fig. 


FOUNDRY  PRACTICE 


127 


67.  This  core  is  18  in.  in  diameter  at  the  base,  4  in.  at 
the  top,  and  30  in.  long.  The  core  rests  on  prints  at  each 
end,  so  must  be  sufficiently  strong  at  the  small  end  to 
sustain  the  weight  of  the  core  when  placed  in  the  mold. 

The  box  is  placed  upon  a  plate  having  a  smooth  face. 
A  little  dry  sand  is  sprinkled  over  the  plate  to  prevent 
the  core  from  sticking  to  it.  Core  sand  is  then  filled  in  to 
a  depth  of  about  2  in.  A  rod  about  26  in.  long  is  wet 


Fig.  67. 

with  paste  and  placed  in  the  centre  of  the  box  and  bed- 
ded into  the  sand.  Sand  is  then  filled  in  and  rammed 
with  the  pein  until  it  is  nearly  of  the  required  size.  The 
last  sand  is  butted  onto  the  surface  making  a  solid  core 
to  strike  off.  A  few  vents  are  directed  to  the  centre  of 
the  lower  side  from  the  larger  portions  of  the  core. 

The  face  of  the  core  is  struck  off  by  maintaining  the 
notch  A  against  the  end  of  the  box  and  always  keeping 
the  face  of  the  strike  directed  radially  to  the  centre 
line  of  the  core.  The  surface  is  slicked  and  brought  to 
an  even  smooth  surface.  The  box  is  then  drawn  from 
the  core. 


128  FOUNDRY  PRACTICE 

The  second  half  is  made  in  the  same  manner.  The 
two  halves  are  blackened  with  a  medium  thick  mixture 
of  the  blacking  and  are  put  in  the  oven  and  dried.  They 
are  then  placed  together  and  rubbed  to  give  a  good  bear- 
ing. The  two  ends  should  be  triec  with  a  caliper  for 
the  correct  diameter.  When  too  large,  the  core  should  be 
rubbed  down  until  the  proper  diameter  is  reached.  The 
halves  are  then  taken  apart  and  the  vent  gutter  is  cut 
through  the  centre  the  full  length  of  the  core  and  on 
both  halves.  This  should  connect  the  vents  previously 
made  through  the  body  of  the  green  core.  The  sand 
and  dust  are  removed  from  the  face  of  the  joint  and 
paste  is  put  upon  one-half  of  the  core.  The  paste  should 
be  strung  along  in  a  thick,  narrow  row  midway  between 
the  edge  and  the  vent  gutter.  If  spread  thin  over  the 
surface  it  may  not  give  contact  at  a  portion  of  the  face. 
When  left  on  thick,  it  squeezes  out  when  the  core  is  put 
together  and  makes  a  firm  joint.  Care  must  be  taken 
to  prevent  filling  the  vent  gutter  \vith  paste  when  the 
core  is  put  together,  thus  closing  the  vent  passage. 

The  half  without  the  paste  is  then  placed  upon  the 
other  and  the  two  pressed  together  with  a  little  rub- 
bing to  force  the  excess  of  paste  out  of  the  joint.  The 
openings  still  left  at  the  joint  on  the  sides  of  the  core 
should  be  filled  with  stiff  blacking  if  small,  but  when 
large  pieces  may  have  broken  off,  the  face  of  the  hole 
is  covered  with  paste  and  core  mixture  is  pressed  in 
to  fill  to  the  desired  surface.  The  face  of.  the  joint  may 
be  smoothed  by  going  over  with  wet  blacking  on  a 
swab  or  brush.  After  the  paste  and  blacking  are  dried, 
the  core  is  ready  for  use  in  the  mold. 

The  skeleton  box  and  strike  may  be  made  use  of 
under  greatly  varying  conditions.  Whenever  there  is  a 


FOUNDRY  PRACTICE  129 

core  or  portion  of  a  core  that  may  be  struck  into  the 
desired  form  with  a  strike,  the  skeleton  box  may  be 
made  use  of.  The  most  general  use  is  found  in  making 
round  cores,  especially  of  large  sizes.  The  strike  in 
this  case  is  straight.  The  strike  or  former  is  also  used 
to  move  lengthwise  of  the  core  instead,  of  crosswise  or 
around  the  core.  In  making  cores  for  water  pipe  specials, 
as  ells,  tees,  etc.,  a  former  is  made  of  the  desired  semi- 
circumference,  and  the  core  is  shaped  by  guiding  upon 
the  skeleton  box  or  upon  a  core  plate  made  to  the  de- 
sired outline. 

The  head  stock  core,  shown  in  Fig.  36,  is  made  in  a 
half  box  having  loose  pieces  to  form  the  recesses  for 
the  bearings.  The  halves  are  made  the  opposite  way  by 
having  reversible  parts  to  the  one  box  or  by  having 
two  separate  boxes.  The  preferable  way  is  to  have  the 
one  frame  with  the  loose  piece  to  make  the  desired  parts. 
This  core  is  thick  enough  to  have  the  "necessary  strength 
without  rodding.  The  box  is  filled  about  4  in.  with  core 
sand  and  rammed  with  a  small  pein  rammer.  The 
loose  pieces  are  put  in  place  and  the  core  sand  is 
bedded  under  and  around  them,  care  being  used  to 
ram  it  sufficiently  and  to  keep  the  pieces  in  their  proper 
position.  The  remainder  of  the  box  is  filled,  rammed 
and  butted  off.  The  face  is  struck  off  and  surfaced  with 
the  trowel  even  with  the  top  of  the  box.  Vent  gutters 
are  cut  to  lead  off  at  the  print  side.  Slant  vents  are 
directed  from  the  gutter  under  the  loose  pieces  and 
into  the  body  portions  of  the  core.  The  loose  pieces  are 
then  drawn  from  the  box.  The  face  is  slicked,  if  nec- 
essary, then  the  opening  is  filled  with  molding  sand  of 
the  usual  temper  for  molding.  This  supports  the  over- 


130 


FOUNDRY   PRACTICE 


hanging  portion   of   the   core   while   it   is   green   and    is 
easily  removed  when  dry. 

A  core  plate  is  placed  on  the  box  and  the  box  is 
turned  over,  holding  the  two  firmly  together.  The  box 
is  rapped  on  all  sides,  then  drawn  vertically  with  light 
rapping  on  the  outside  of  the  box.  The  core  is  slicked, 
then  dampened  on  the  face  with  water  and  placed  in 
the  oven  for  drying.  The  face  of  the  core  is  dampened 
to  form  a  harder  skin  when  the  core  is  dried.  If  too 
much  water  is  put  on  at  any  spot,  it  washes  away  the 
binder  leaving  the  face  soft  and  rough  with  loose  sand. 
The  water  may  best  be  sprinkled  on  the  core  by  wetting 
a  brush  and  throwing  the  water  from  it  by  holding  the 


] 


Fig.  68. 

hand  and  striking  the  brush  against  it  with  the  other 
so  that  the  jar  throws  the  water.  With  a  little  prac- 
tice the  core  may  be  dampened  just  as  desired  by  this 
method.  A  more  convenient  method  of  dampening  the 
core  is  by  use  of  the  spray  can  or  spraying  bellows. 

The  core  is  blackened,  pasted,  and  finished  as  in 
the  previous  case,  giving  the  completed  core  desired. 

A  simple  form  of  core  using  a  special  anchor  may 
be  found  in  making  a  large  round  core  for  a  cylinder. 
Fig.  68  shows  an  anchor  for  half  of  a  core  for  a  cylinder 
48  in.  in  diameter.  The  anchor  was  made  for  a  skeleton 
box. 


FOUNDRY  PRACTICE  131 

The  method  of  making  the  core  may  be  explained 
briefly  as  follows.  The  box  is  placed  upon  a  smooth, 
even  plate  easily  accessible  to  the  drying  oven.  The 
core  sand  is  riddled  evenly  over  the  surface  enclosed  by 
the  box  to  a  thickness  of  about  i  in.  The  anchor  is 
coated  with  flour  paste  or  clay  wash  and  placed  in  po- 
sition within  the  box.  When  the  anchor  is  light  it  should 
be  rapped  down,  then  tucked  all  around  to  ensure  an 
even,  hard  core  under  the  anchor.  The  core  sand  is 
filled  in  and  peined  firmly.  Each  layer  should  be  but 
3  or  4  in.  in  thickness.  After  the  anchor  is  covered  to 
a  thickness  of  about  2  in.  the  core  is  vented,  leading 
toward  the  centre.  A  bed  of  coke  is  laid  through  the 
centre  about  10  in.  wide  and  5  in.  deep.  Long  rods 
are  laid  in  near  the  wrought  iron  bands  to  firmly  tie 
the  sand  between  them.  Rods  are  placed  at  the  outer 
rim  at  intervals  of  2  or  3  in.  as  the  core  is  rammed. 
This  size  of  core  must  be  very  solid  in  order  to  have 
sufficient  strength  to  carry  its  own  weight. 

While  ramming,  it  saves  time  to  fasten  pieces  onto 
the  outside  of  the  frame  of  the  box  to  hold  the  core 
to  the  desired  form.  Without  the  pieces  on  the  sides,  the 
sand  will  crush  out  or  expand  at  the  bottom  while  ram- 
ming on  the  upper  portion  of  the  core.  When  the  ram- 
ming is  completed,  the  pieces  are  taken  off  the  side  and 
the  entire  core  is  vented  to  the  coke  centre.  It  is  then 
struck  off  and  the  surface  slicked  to  a  smooth,  even  face. 
This  anchor  is  provided  with  nuts  into  which  screw 
eyes  are  placed  for  handling  the  core.  The  screw  eyes 
are  left  in  while  ramming  the  core.  The  rods  must  be 
kept  at  least  an  inch  from  the  screw  eye  so  that  th^y 
will  not  be  loosened  when  the  screw  eye  is  removed. 

The  box  may  be  taken   from  the   core  and   the   re- 


132  FOUNDRY   PRACTICE 

mainder  of  the  core  is  slicked.  Wet  blacking  is  put  even- 
ly over  the  surface.  The  blacking  should  be  as  thick 
as  will  spread  readily  and  evenly.  The  core  is  then 
ready  to  dry. 

The  other  half  has  the  nuts  in  the  anchor  offset  from 
those  in  the  first  half,  so  that  openings  may  be  left 
through  the  entire  half  directly  over  the  nuts  in  the  pre- 
vious one.  When  the  core  is  together  finished,  the  screw 
eyes  are  fastened  into  the  lower  half  of  the  core.  The 
second  half  is  made  the  same  as  the  first  except  that 
round  sticks  are  placed  exactly  in  the  position  of  the 
nuts  of  the  first  half. 

The  core  should  be  pasted  while  one-half  is  hot  'n 
order  to  dry  the  paste.  The  crack  aJ  the  parting  is  filled 
with  hard  blacking  or  core  sand,  then  coated  with  black- 
ing and  dried  by  replacing  in  the  oven  or  by  a  fire  built 
around  the  core. 

The  same  core  may  be  made  in  many  other  ways, 
dependent  upon  the  appliances  available.  The  principles 
are  similar  in  making  all  cores  having  special  anchors 
All  large  cores  must  have  special  frames  or  anchors 
to  give  them  strength.  The  forms  of  these  anchors  and 
the  fitting  for  handling  are  nearly  as  various  as  the 
different  cores  in  which  they  are  used. 

In  many  cases  the  core  is  nearly  submerged  in  iron 
when  the  mold  is  poured.  These  cores  must  be  made 
so  as  to  give  very  free  vent  to  the  gases  in  order  to 
prevent  blowing  in  some  part.  Where  the  core  is  large 
enough  to  easily  collect  the  gases  at  its  centre  and 
lead  them  off  through  the  print,  the  core  may  be  made 
very  similar  to  other  cores.  When  the  core  is  thin  or 
so  shaped  that  proper  venting  is  difficult  to<  obtain,  the 


FOUNDRY  PRACTICE 


133 


mixture  should  be  such  as  to  give  a  hard  core  with  as 
little  gas  as  possible. 

The  core  shown  in  Fig.  69  is  for  forming  a  pocket 
in  a  crank  disk  which  will  be  filled  with  lead  as  the 
counter  weight  for  balancing  the  engine.  The  core  here 
shown  is  a  semicircular  segment  whose  inner  radius 
is  10  in.  and  outer  radius  21^/2  in.  The  thickness  is 
3  in.  with  4  openings  on  one  side  2^/2  in.  in  diameter. 
This  core  is  surrounded  except  for  the  openings  through 
which  the  vent  is  led  off. 

To  make  this  core,  the  mixture  given  in  Receipt  No. 


Fig.  69. 

II  proved  very  satisfactory.  Procure  4  pieces  of  wrought 
iron  pipe  I  in.  or  1^4  in.  in  diameter  and  4  in.  long. 
Burr  out  one  end  so  that  the  pipe  bulges  bell-shaped. 
Cover  the  pipe  well  with  linseed  oil,  then  place  in  the 
centre  of  each  print  or  opening  and  fill  in  with  the  core 
sand.  This  pipe  extends  to  the  centre  of  the  core  where 
the  gases  are  led  off.  The  entire  box  is  filled  in  a  little 
over  an  inch  in  depth  with  the  core  sand  and  rammed. 
Wires  are  laid  in  to  bind  the  core.  These  wires  should 
be  of  such  a  size  as  to  hold  the  core  and  still  be  easy  to 
remove  from  the  casting  through  these  small  openings 


134  FOUNDRY   PRACTICE 

of  2l/2  in.  in  diameter.  These  wires  are  laid  in  length- 
wise of  the  core,  placing  one  near  the  outer  circle  and 
one  near  the  inner,  while  one  is  placed  about  an  inch 
away  from  the  pipes  on  either  side  of  it.  The  wires  are 
bedded  into  the  sand  now  in  the  box.  Sand  is  filled  in 
to  the  level  of  the  top  of  the  vent  pipe. 

Vent  gutters  are  laid  out  just  inside  of  the  outer 
wires,  with  a  similar  one  through  the  centre  to  connect 
the  vent  pipes.  Cross  gutters  connect  the  ends  and  join 
the  outer  gutter  at  each  of  the  pipes,  and  similarly  mid- 
way between  the  vent  pipes.  These  gutters  are  maclt 
to  a  depth  of  about  l/2  in.  below  the  centre.  Fine  coke 
is  laid  in  the  gutter  to  a  depth  of  about  I  in.  The 
coke  taken  is  that  which  will  pass  through  a  No.  2  rid- 
dle and  will  not  pass  through  a  No.  6.  The  coke 
is  then  covered  with  coarse  sharp  sand  or  fine  gravel 
to  prevent  the  core  sand  filling  up  the  openings  between 
the  coke.  This  should  bring  the  sand  above  the  top 
of  the  pipes.  The  pipes  should  be  filled  with  waste  or 
anything  to  prevent  the  sand  from  filling  them,  and  the 
waste  may  be  removed  after  the  core  is  finished.  The 
top  of  the  pipes  is  covered  with  coke  to  connect  freelv 
with  the  vent  gutters.  This  is  covered  with  sand  the 
same  as  the  gutters.  Core  sand  is  filled  in  to  the  top 
of  the  gutters  and  rammed.  Cross  wires  are  laid  at 
distances  of  about  4  or  5  in.  to  bind  the  core  togethet. 
A  little  more  sand  is  filled  in  over  the  entire  surface  ot 
the  box  and  long  rods  laid  in  as  before.  The  remain- 
der of  the  box  is  filled  and  rammed.  The  top  is  struck 
off  even  with  the  box  and  the  face  slicked  smooth  with 
the  trowel.  Parting  sand  or  dry  sharp  sand  is  dusted 
over  the  face  to  prevent  its  sticking  to  the  plate.  A 
straight  plate  is  clamped  onto'  the  core  box  and  turned 


FOUNDRY   PRACTICE  135 


136  FOUNDRY  PRACTICE 

over,  when  the  box  may  be  removed  giving  the  core  as 
desired. 

Oil  or  core  compound  readily  bakes  onto  a  plate  so 
as  to  stick  the  core  to  it.  When  making  those  cores, 
something  must  be  put  onto  the  plates  to  prevent  the  oil 
from  fastening  to  the  plates.  Other  cores  separate  read- 
ily from  the  plates  after  drying. 

The  round  cores  of  various  sizes  are  used  in  so  many 
different  castings  that  all  foundries  keep  a  supply  of 
each  size  in  stock.  These  may  be  cut  to  the  length  de- 
sired in  any  case.  This  is  a  much  cheaper  method 
than  making  special  cores  for  each  pattern  used.  The 
boxes  for  cores  up  to  4  in.  in  diameter  are  made  sim- 
ilarly to  those  shown  in  Fig.  65,  and  of  a  standard  length. 

Machines  have  been  invented  for  making  these  stock 
cores  which  greatly  reduces  the  cost  of  labor.  These 
machines  are  made  with  changeable  parts  for  making 
cores  up  to  about  2  in.  in  diameter.  There  are  several 
manufactories  making  machines  for  this  purpose.  The 
Hammer  core  machine  shown  in  Fig.  70  is  fitted  to 
make  cores  from  ^  in.  to  2  in.  in  diameter.  The  mix- 
ture is  placed  in  the  hopper  and  by  turning  the  crank 
wheel,  the  mixture  is  forced  through  the  tube  of  the  de- 
sired size  by  a  bit  directly  back  of  the  tube.  These 
give  a  core  vented  in  the  centre  throughout  its  length 
and  of  an  even  hardness.  The  ramming  is  dependent 
upon  the  friction  of  the  sand  on  the  tube  through  which 
the  core  passes. 

The  mixture  that  makes  a  very  good  core  is  one  with 
oil  and  flour  as  a  binder. 


CHAPTER  IV 

Dry  sand  molds  are  made  similarly  to  green  sand 
mold,  using  special  facings.  The  mold  is  blackened  with 
a  wet  blacking  and  slicked  smooth,  then  dried  in  an 
oven  or  by  special  drying  apparatus.  The  surface  after 
drying  is  hard,  similar  to  a  brick.  This  gives  a  surface 
that  can  withstand  great  pressures  where  a  high  head 
is  necessary  in  casting.  The  dry  face  coated  with  the 
blacking  prevents  fusion  of  the  sand  and  thus  gives 
a  smooth  casting.  Hence  where  it  is  desirable  to  have 
a  smooth  casting  or  when  the  head  pressure  is  great,  dry 
sand  or  loam  molds  are  used. 

The  mixture  used  next  to  the  pattern  in  dry  sand 
work  is  called  the  dry  sand  facing.  That  used  to 
fill  in  between  the  facing  and  the  flask  is  called  the 
backing  sand.  Old  molding  sand  forms  a  good  backing. 
Dry  sand  facing  comprises  a  mixture  which  will  become 
hard  and  strong  when  dried  and  still  be  open  to  allow 
free  escape  of  the  gases.  The  mixture  for  the  dry  sand 
facing  is  dependent  upon  the  sand  obtainable  in  the  lo- 
cality. A  sand  too  strong  with  clay  gives  the  hard, 
strong  face  to  the  mold  but  will  not  allow  the  gases  to 
escape.  Where  the  molding  sand  is  of  a  fine  quality  and 
quite  strong  with  clay,  Receipts  Nos.  i  and  2  will  make 
a  good  facing.  The  proportion  of  sharp  or  lake  sand 
may  be  varied  where  the  facing  is  found  to  be  too  close 
or  too  open. 


138  FOUNDRY  PRACTICE 

Receipt  No.   i.     Mix  i  part  new  molding  sand,   i   part 

old  molding  sand,  and  2  parts  sharp  or  core  sand.    To 

30  parts   of  sand  add   i   part   flour  and    i    part   sea 

coal.     Wet  with  water. 
Receipt   No.  2.     Mix  4  parts   of  molding  sand   with   i 

part  sharp  or  lake  sand.     To  30  parts  of  sand  add 

i  part  of  flour.     Wet  with  clay  wash. 
Receipt   No.   3.     Mix    i    part  of  molding   sand   with    i 

part  of  bank   sand.     To  30  parts   of   sand  add   1^/2 

parts  of  sea  coal  and  i  p'art  of  flour.     Wet  with  clay 

wash. 

Dry  sand  may  be  rammed  much  harder  than  green 
sand.  The  facings  are  more  open  and  the  moisture  is 
evaporated  from  it  before  casting.  The  ramming  should 
be  even,  because  unevenness  may  cause  trouble  similar 
to  green  sand  though  not  so  readily.  Hard  spots  in 
the  face  of  a  dry  sand  mold  will  cause  a  scab  on  the 
casting. 

The  importance  of  venting  dry  sand  must  not  be 
underestimated.  After  the  mold  is  dried  there  is  no 
moisture  to  form  steam  as  in  the  green  sand  mold. 
The  other  gases  are  still  formed  at  the  face  of  the  cast- 
ing and  must  be  carried  away  or  the  casting  is  liable 
to  blow  or  scab.  When  there  is  6  in.  or  more  of  sand 
between  the  casting  and  the  flask  no  venting  is  neces- 
sary. When  less  than  6  in.  there  is  not  sufficient  space 
to  relieve  the  pressure  unless  there  are  holes  in  the  flask 
for  release  or  vents  for  carrying  off  the  gases. 

As  the  body  of  sand  increases,  the  pressure  of  the 
gases  decreases,  hence  the  smaller  the  body  of  sand 
the  greater  the  necessity  of  vents.  Large  bodies  of 
sand  give  relief  to  the  pressure  through  its  openings 
or  porosity.  It  literally  holds  the  gases  without  in- 


FOUNDRY  PRACTICE  139 

creasing  the  pressure  to  a  dangerous  degree.  Pockets, 
corners,  flanges,  and  similar  projections  require  venting 
and  provision  for  conducting  off  the  gases,  but  not  so 
extensive  as  in  green  sand  molds. 

In  green  sand,  when  the  joint  comes  together  closely, 
it  may  compress  slightly  without  damage  when  the  flask 
is  clamped.  In  dry  sand,  the  hard  surface  will  not  admit 
of  any  compression  without  breaking  away.  This  is 
avoided  by  cutting  away  the  joint  slightly  at  the  edge 
of  the  pattern  before  or  after  drawing.  This  leaves 
a  fin  on  the  casting  which  may  be  chipped  off.  The 
edges  where  cores  bear  should  be  similarly  treated. 
This  fin  should  be  from  l/%  in.  to  *4  m-  m  thickness  and 
should  slope  back  about  3  in.  The  maxim  "It  is  better 
to  have  a  fin  than  a  crush"  should  be  remembered  in  drv 
sand  work. 

The  finishing  of  dry  sand  molds  gives  the  face  which 
causes  the  casting  to  peel.  After  the  pattern  is  removed 
the  face  of  the  mold  is  dampened  with  molasses  water 
or  beer  wash.  This  makes  the  facing  stick  together  firmly 
and  gives  a  smooth  compact  surface  when  slicked. 
The  flour  in  the  facing  makes  it  rather  pasty  so  it  can 
be  shaped  more  easily  than  a  green  sand  mold.  The 
entire  face  is  slicked  with  the  tools  before  blackening. 
Any  part  torn  by  the  pattern  may  be  patched  similarly  to 
a  green  sand  mold.  The  face  of  the  mold  may  be  slicked 
much  harder  than  in  a  green  sand  mold.  The  sand  is 
much  more  open  and  held  together  by  the  flour  so  it  will 
not  scab  so  easily  as  green  sand. 

The  blacking  is  put  upon  the  dry  sand  mold  to  close 
the  pores  of  the  sand  and  give  a  smooth  surface  that 
will  peel  from  the  casting.  The  mixtures  given  below 
have  yielded  very  good  results.  The  proportions  may 


140  FOUNDRY  PRACTICE 

be  varied  to  suit  the  qualities  of  the  ingredients  and  to 
give  better  results  in  particular  cases.  When  the  black- 
ing cracks  or  peels  upon  drying,  the  body  has  been  put 
on  too  heavy  or  there  is  too  great  a  percentage  of  clay 
wash. 

Receipt  No.  I  is  used  for  light  castings  or  where 
the  thickness  of  metal  is  less  than  2  in.  Receipt  No.  2 
is  better  for  heavy  or  thick  castings.  Receipt  No.  3  is  a 
very  simple  mixture  which  gives  good  results  on  small 
or  thin  castings. 

Receipt  No.  I. — Mix  i  part  charcoal  blacking,  i  part 
Lehigh  blacking,  2  parts  plumbago.  Wet  with  mo- 
lasses water  or  sour  beer. 

Receipt  No.  2. — Mix  8  parts  charcoal  blacking,  8  parts 
plumbago,  i  part  thick  clay  wash.  Wet  with  sour 
beer  and  allow  to  stand  2  or  3  days  before  using. 
Receipt  No.  3. — Mix  a  clay  wash  from  red  clay  of  a 
thickness  that  will  color  the  hand  when  dipped  into 
it.  Add  plumbago  until  it  becomes  of  the  thickness 
desired. 

The  molds  are  dried  by  heating  sufficiently  to  drive 
off  the  water  from  the  sand.  This  is  accomplished  in 
many  different  ways  to  suit  the  conditions.  The  best 
method  is  to  dry  the  mold  in  an  oven.  The  oven  for 
this  purpose  is  similar  to  the  core  ovens  which  admit 
a  core  car.  The  molds  are  put  on  the  car  for  placing 
in  the  oven.  The  temperature  is  kept,  between  500° 
and  600°  F.  This  will  not  burn  the  face  of  the  mold  and 
dries  it  very  rapidly. 

Some  molds  are  dried  by  injecting  hot  air.  The  mold 
is  closed  with  the  pipes  from  a  heater  projecting  into  it. 
All  the  openings  and  the  parting  are  sealed  with  clay 
to  resist  the  air  pressure.  The  air  i?  kept  under  a  small 


FOUNDRY  PRACTICE  141 

pressure  which  forces  it  out  through  the  sand  and  vents. 
The  heat  dries  the  sand  giving  the  desired  result.  One 
form  of  apparatus  to  accomplish  this  would  consist  of 
a  heater  or  large  stove  having  a  coil  of  pipe  in  the  place 
of  the  lining.  The  air  is  forced  through  this  by  a 
root  blower.  The  blower  is  driven  by  a  motor  or  belted 
from  a  shaft.  The  coil  in  the  heater  is  connected  to  the 
mold  by  a  pipe.  The  heater  should  be  as  close  to  the 
mold  as  convenient  to  reduce  the  cooling  of  the  air  be- 
fore reaching  the  mold. 

Another  common  method  of  drying  is  to  use  the  fire 
pot.  A  charcoal  fire  is  built  in  a  fire  pot  and  lowered 
into  the  mold.  It  should  be  kept  at  equal  distances  on 
all  sides  from  the  faces  to  be  dried.  The  fire  pot  should 
conform  to  the  general  shape  of  the  mold.  This  gives 
unequal  drying  on  an  irregular-shaped  mold.  When 
carefully  followed  very  satisfactory  results  are  obtained. 

The  face  of  the  parting  is  slicked  down  before  dry- 
ing, so  that  the  sand  does  not  touch  when  the  flask  is 
closed.  It  is  therefore  necessary  to  place  upon  the  face 
of  the  parting  something  that  will  seal  this  opening  and 
hold  the  metal.  A  stiff  dough  made  of  flour  and  water, 
then  rolled  out  into  long  strings,  serves  the  purpose 
The  dough  will  flatten  without  damage  to  the  mold,  when 
the  two  parts  of  the  mold  come  very  near  together. 
These  strings,  often  called  noodles,  are  placed  around 
the  edge  of  the  mold  and  over  cores  which  should  beat 
on  the  cope. 

Dry  sand  may  be  employed  without  the  use  of  fac- 
ing. It  is  claimed  by  many  of  the  best  foundrymen  that 
it  is  unnecessary  to  use  flour  and  sea  coal  in  the  facing 
for  a  dry  sand  mold  where  a  good  blacking  is  used.  The 
object  of  the  flour  is  to  make  the  face  hard  when  dryr 


142  FOUNDRY  PRACTICE 

as  a  core.  The  sea  coal  is  to  prevent  fusion  of  the  sand 
and  to  peel  the  casting.  For  the  medium-sized  cast- 
ing in  dry  sand  the  facing  used  is  i  part  new  molding 
sand  with  i  part  old  molding  sand  wet  with  clay  wash 
and  riddled  through  a  No.  6  riddle.  The  backing  may 
be  of  the  coarsest  heap  sand.  The  blacking  for  the 
mold  is  made  from  Receipt  No.  3.  Castings  made  by 
this  method  have  been  found  to  peel  and  to  leave  as 
smooth  and  bright  a  surface  as  any  dry  sand  mold. 

In  many  cases  where  previously  dry  sand  molds 
were  used,  it  is  found  as  satisfactory  to  only  skin-dry 
the  mold.  The  mold  is  handled  in  the  same  manner 
as  a  dry  sand  mold,  but  the  drying  is  continued  only 
long  enough  to  dry  the  sand  for  a  depth  of  about  2  in. 

Some  kinds  of  sand  which  are  quite  strong  with  clay 
do  not  require  the  flour  used  in  the  dry  sand  facing,  but 
hold  well  when  moistened  with  clay  wash,  molasses  wa- 
ter, or  beer  wash.  Generally  the  same  facing  is  used  as 
in  dry  sand  molds. 

A  skin-dried  mold  has  the  hard  surface  but  the  back- 
ing  is  still  soft.  This  increases  the  danger  of  crushing 
when  closed  and  of  the  cutting  o  f  the  metal  when  poured. 
The  mold  should  be  cut  away  at  the  parting  and  the 
entire  joint  slicked  down  slightly  to  ensure  the  bearing 
on  the  flask  instead  of  on  the  sand.  The  dried  crust  wil< 
separate  from  the  green  backing  much  more  easily  than 
a  dried  mold  would  break.  When  a  casting  is  so  gated 
that  it  would  be  liable  to  cut  if  the  sand  were  green,  it 
should  be  well  nailed  in  front  of  the  gate  before  skin- 
drying. 

The  face  of  the  mold  is  finished,  blackened,  and 
slicked  the  same  as  in  dry  sand.  The  blacking  may  1>e 


FOUNDRY  PRACTICE  I4J 

put  on  dry,  then  moistened  with  molasses  water;  or,  bet- 
ter, the  wet  blacking  mixture  may  be  used. 

A  mold  is  skin-dried  by  the  same  method  used  for 
dry  sand  molds.  For  slightly  drying  the  face  of  small 
molds,  gasoline  may  be  sprayed  on  the  surface  and 
burned  off,  giving  a  hard  face.  This  may  be  used  with 
some  kinds  of  sand  in  the  common  green  sand  mold, 
giving  the  casting  the  appearance  of  coming  from  a  dry 
sand  mold.  It  gives  a  smoother  casting  in  small  work 
than  the  wet  face. 

Many  castings  can  not  be  easily  made  in  a  flask,  owing 
to  their  size  or  form.  These  are  made  into  the  floor 
with  a  cope  to  cover  a  part  or  the  whole.  This  division 
of  molding  is  called  pit  molding.  Fly  wheels,  large 
sheaves,  and  large  gears  are  made  in  this  way  more 
easily  than  in  the  drag  of  a  flask.  Many  large  cast- 
ings that  might  otherwise  be  made  in  a  flask  are 
bedded  into  the  pit  when  there  is  no  flask  at  hand. 
It  is  much  cheaper  to  bed  the  pattern  into  the  floor  than 
it  would  be  to  make  a  flask  when  only  one  casting  is  de^ 
sired.  Some  molds  are  subjected  to  an  intense  down 
and  side  pressure  when  the  metal  is  poured.  It  would 
require  a  very  strong  flask  to  withstand  this  stress,  hence 
it  would  be  very  expensive.  If  placed  in  the  pit,  the 
sand  is  rammed  hard  to  the  adjoining  ground,  hence  the 
pressure  is  resisted  except  that  on  the  cope  which 
must  be  provided  for  by  weights  or  the  cope  must  be 
bolted  to  anchors  in  the  ground. 

Since  there  is  no  opening  at  the  bottom,  as  in  the 
case  of  a  flask,  for  the  escape  of  the  gases,  provision 
must  be  made  to  carry  these  off  from  the  bottom  of  the 
mold.  Below  the  mold  at  a  depth  of  about  2  ft.,  a  layer 
of  coke  or  cinders  is  placed  to  collect  the  gases.  This 


144 


FOUNDRY  PRACTICE 


oo         oooooo 
oooooooo 

;   o 

i     0 

x^ 

1       :    .            !    i             ;    :             •    !             :    :  •          :    :             :    :            :    : 

(        A  i 

D 


B 

© 


Fig.  71. 


FOUNDRY  PRACTICE  145 

coke  bed  is  connected  to  the  surface  by  a  vent  pipe.  All 
the  vents  from  the  lower  portion  of  the  mold  extend 
through  to  this  coke  bed  which  gives  relief  to  the  gases. 

To  make  the  coke  bed  the  pit  is  dug  out  about  il/2 
or  2  ft.  deeper  than  the  mold  would  require.  It  is 
then  leveled  off  and  a  layer  of  coke  of  about  the  size  of 
an  egg  is  put  in  to  a  thickness  of  2  or  3  in,  The  coke 
is  covered  with  hay,  straw,  or  gunny  sacks  to  keep  the 
sand  from  packing  solid  around  the  coke.  A  pipe  of 
ample  size  to  give  free  vent  to  the  bed  is  placed  at  the 
outside  to  connect  with  the  surface.  The  lower  end  of 
the  pipe  rests  on  the  coke  and  is  so  covered  with  coke 
that  the  sand  can  not  enter  the  pipe.  The  sand  may 
now  be  filled  in  to  form  the  mold  above. 

Making  castings  by  use  of  sweeps,  in  the  place  of 
patterns,  is  being  extensively  practiced  where  but  a  sin- 
gle casting  is  required.  The  time  required  for  making 
such  a  mold  is  greater  than  that  required  where  a  pat- 
tern is  used,  but  the  expense  of  making  the  pattern  is 
saved,  except  for  forming  the  sweeps  which  is  very 
slight. 

A  simple  form  of  the  necessary  rigging  is  illustrated 
in  Fig.  71.  The  socket  A  is  a  cast  base  having  a  tapered 
hole  in  the  centre  for  holding  the  spindle.  The  spin- 
dle B  is  made  of  steel  or  cast  iron,  and  is  uniform  in 
diameter,  having  its  lower  end  tapered  to  fit  the  socket. 
A  collar  is  fitted  to  the  spindle  and  has  a  set  screw  for 
fastening  it  at  any  point.  This  carries  the  sweep  arm 
at  the  desired  height.  The  revolving  arm  D  is  made  of 
cast  iron,  bored  to  fit  the  spindle  and  having  slots  for 
bolting  the  sweep  and  allowing  adjustment.  The  sweep 
is  made  of  wood  having  the  special  shape  for  the  desired 
casting. 


146 


FOUNDRY  PRACTICE 


The  process  of  forming  a  green  sand  mold  by  use  of 
a  sweep  may  be  noted  in  making  ?.  cover  as  shown  in 
Fig.  72.  A  hole  is  dug  into  the  floor  and  the  socket 
is  bedded  in  so  as  to  hold  the  spindle  plumb.  A  coke 
bed  is  formed  around  it  with  the  vent  pipes  leading  to  the 
surface.  Sand  is  filled  in  and  rammed  to  a  level  shown 


Fig.  72. 

by  line  M'N,  Fig.  73.  This  is  well  vented  to  the  coke 
bed  with  a  Y%  in.  wire.  Facing  sand  is  filled  in  and 
rammed  to  the  height  that  it  is  to  be  struck  off  and  to 
approximately  conform  to  the  line  ACB  of  the  top  of  the 
cover.  The  sweep  arm  is  placed  upon  the  spindle  above 
the  collar  C.  The  sweep  is  made  to  conform  exactly 
to  the  upper 'face  of  the  cover.  It  is  fastened  to  the  arm 


FOUNDRY  PRACTICE  147 

so  as  to  have  the  outer  end  at  A  strike  a  level  face, 
which  gives  the  guide  for  the  location  of  the  sweep  to  be 
used  later.  The  collar  is  adjusted  to  give  the  outer  edge 
of  the  cover  at  the  floor  line.  The  surface  ACB  is 
swept  by  revolving  the  sweep  away  from  the  cutting 
edge  as  indicated  at  H. 

The  sweep  and  collar  are  removed  and  the  surface 
slicked  for  a  parting  surface  as  usual.  Parting  sand 
is  then  put  upon  the  surface  and  a  cope  placed  in  posi- 
tion and  staked  at  the  corners  to  allow  replacing  after 


Fig.  73- 

removing  for  finishing  the  mold.  A  short  pipe  or  box 
is  placed  around  the  spindle  to  allow  lifting  the  cope 
as  at  P,  Fig.  73.  The  cope  is  rammed  as  usual  with 
the  necessary  gates  and  risers.  The  cope  is  lifted  off, 
finished  and  blackened.  The  pipe  at  the  centre  is  drawn 
back  and  filled,  then  faced  to  the  desired  surface  of  the 
cope,  care  being  used  to  properly  vent  it.  A  second 
sweep,  E,  Fig.  74,  is  placed  upon  the  spindle  which  ex- 


148 


FOUNDRY  PRACTICE 


actly  conforms  to  the  under  side  of  the  cover,  having 
the  edge  A  as  a  gauge  for  the  depth  and  following  the 
level  surface  previously  swept.  The  collar  on  the  spin- 
dle is  adjusted  so  that  the  level  face  of  the  sweep  just 
touches  the  level  face  previously  swept,  then  the  drag 
is  swept  out  to  the  desired  shape.  The  sweep  and  spin- 
dle are  now  removed  and  the  face  of  the  mold  finished. 
The  opening  left  by  the  spindle  is  filled  with  cinders 
nearly  to  the  surface,  then  facing  sand  is  rammed  in 
until  the  desired  face  is  reached.  The  drag  is  finished 
and  blackened,  with  the  gates  and  risers  properly  con- 
nected to  the  mold.  The  cope  may  be  replaced  by  aid  of 
the  stakes,  which  completes  the  mold  as  shown  in  Fig. 
75- 


Fig.  74- 

Methods  of  casting  fly  wheels  are  various.  Fly 
wheels  are  made  from  part  patterns  which  are  moved 
about  a  centre  spindle.  The  arms  are  made  in  core, 
while  the  rim  may  be  in  green  sand,  core  sand  or  loam. 
The  method  of  procedure  in  making  a  mold  for  a  fly 
wheel  will  be  given  in  a  general  way,  for  the  details 
can  not  be  understood  until  the  actual  experience  has 
been  met  with. 

The  coke  bed  is  made  under  the  rim  to  extend  inside 


FOUNDRY  PRACTICE 


149 


part  way.  The  socket  for  the  spindle  is  set  in  the  centre 
and  below  the  hub  cores.  This  socket  is  so  leveled  that 
the  spindle  stands  exactly  plumb. 

The  bottom  core  for  the  hub  is  located  about  the  spin- 
dle. A  sweep,  so  shaped  as  to  form  a  bed  for  the  arm 
cores  of  the  wheel,  is  then  placed  on  the  spindle.  This 
sweep  has  its  lower  edge  shaped  like  the  strike  stick  pre- 
viously mentioned. 

The  bed  is  rammed  and  struck  off  with  the  sweep  over 
the  entire  portion  within  the  rim  of  the  wheel.  This  gives 
a  bed  such  that  when  the  arm  cores  are  laid  upon  it  the 
centre  line  of  the  arm  is  level. 


Fit?.  75. 

The  arm  cores  are  so  placed  upon  the  bed  that  their 
outer  ends  just  touch  the  inner  face  of  the  pattern  for  the 
rim.  This  is  gauged  by  fastening  a  vertical  piece  onto 
the  sweep  previously  used  at  the  same  radius  as  the  inner 
portion  of  the  pattern.  The  collar  on  the  spindle  is 
fastened  so  as  to  support  the  sweep  above  the  cores.  The 
cores  are  placed  so  the  vertical  piece  on  the  sweep  will 
just  clear  the  end,  thus  giving  the  desired  radius. 

The  pattern  is  placed  upon  the  spindle  and  the  rim  is 


150  FOUNDRY  PRACTICE 

rammed,  a  section  at  a  time.  Each  time  the  pattern  is 
moved  it  is  kept  at  an  exact  level,  thus  when  the  last  sec- 
tion is  made  the  pattern  strikes  exactly  where  it  started. 
With  wheels  having  a  straight  rim  without  flanges,  both 
faces  may  be  rammed  in  green  sand.  Where  there  is  a 
flange  at  both  edges,  various  methods  are  used.  When 
the  rim  is  light  and  the  face  less  than  14  in.,  the  lower 
flange  may  be  made  by  cores  laid  while  ramming  the 
mold,  and  the  outer  face  rammed  at  the  same  time.  When 
large  it  is  preferable  to  make  the  outer  face  in  core  or 
loam.  The  pattern  then  has  a  core  print  below  the  face 
and  one  above  it  and  the  green  sand  is  rammed  only  on 
the  inside  of  the  rim.  The  cores  for  the  face  bear  on  the 
green  sand  above  and  below  the  casting  and  extend 
to  the  inner  face  of  the  flange.  These  cores  are  held  in 
place  by  ramming  the  sand  solid  back  of  the  cores,  bring- 
ing the  floor  level  with  the  top  of  the  core.  The  cores 
may  also  be  held  by  binding  plates  and  supports  to  hold 
the  outward  pressure  on  the  rim  when  the  mold  is  poured. 
When  the  outer  face  is  made  of  green  sand,  the  top  is 
covered  with  cores,  then  weighted  down  to  hold  the  pres- 
sure. 

The  gates  are  placed  on  the  hub  with  a  runner  and 
pouring  basin  leading  to  the  outside  of  the  rim  where  it  is 
accessible  to  the  ladle.  Risers  are  placed  on  the  rim  and 
the  casting  fed  through  the  gates  and  the  risers,  when  the 
rim  is  heavy  enough  to  require  feeding. 

Loam  is  used  to  make  large  molds  of  the  same  type 
as  dry  sand.  Loam  can  be  easily  shaped  by  use  of  a 
sweep,  and  when  dried  will  resist  great  pressures  and  will 
give  a  casting  with  smooth  surface  the  same  as  dry  sand. 
Loam  is  chiefly  used  where  the  whole  or  a  part  is  made 
with  a  sweep. 


FOUNDRY  PRACTICE  151 

Loam  must  be  of  a  very  open  texture  so  that  in  gen- 
eral the  mold  requires  but  little  venting.  Corners,  pock- 
ets, projections,  and  parts  not  having  free  relief  to  the 
gases  are  safer  when  vented  and  these  vents  led  to  the 
outside.  Hard-burned  brick  should  never  be  used  for 
the  face  of  the  mold,  as  it  prevents  the  escape  of  the  gas- 
es. The  courses  of  brick  are  occasionally  separated  by  a 
layer  of  straw  to  give  better  venting. 

The  body  portion  of  a  loam  mold  is  made  of  brick. 
This  conforms  approximately  to  the  pattern  or  desired 
face  of  the  mold.  The  bricks  are  laid  up  in  courses  so  as 
to  break  joints  and  to  bind  the  whole  firmly  together. 
They  are  laid  in  a  coarse,  open  mixture  of  loam  to  aid  the 
escape  of  gases.  The  bricks  must  be  of  a  soft  porous  kind. 
In  some  cases,  bricks  are  made  from  loam  for  forming 
portions  of  the  brick  wall.  These  are  more  porous  and 
crush  more  easily  than  common  bricks  when  the  casting 
shrinks.  They  are  made  from  a  stiff  mixture  of  coarse 
loam  just  soft  enough  to  work  easily.  The  bricks  are 
made  in  the  box  and  laid  on  a  plate  whose  face  has  been 
oiled,  and  are  then  dried  in  the  oven. 

The  bricks  are  given  a  first  coat  of  coarse,  open  loam, 
swept  to  shape,  and  a  second  or  finishing  coat  of  loam 
which  is  finer  and  thinner.  The  thickness  should  never 
be  less  than  ^/%  in.  to  ^4  in-  f°r  plane  surfaces,  and  not 
less  than  i  in.  in  pockets,  projections,  etc.  The  thickness 
of  the  metal  does  not  gauge  the  thickness  of  the  loam,  be- 
cause a  heavy  casting  will  scab  as  quickly  as  a  thin  one. 
The  thicker  the  loam,  the  better  the  venting. 

The  loam  mixture  is  more  of  a  mud  than  that  of 
green  or  dry  sand.  It  contains  much  clay  combined 
with  sharp  sand  and  other  materials  to  make  it  open. 
The  exact  mixture  is  entirely  dependent  upon  the  sand 


152  FOUNDRY  PRACTICE 

used.  In  a  few  places  the  natural  loam  is  found  which 
may  be  used  without  any  additions.  The  mixture  must 
contain  enough  clay  to  hold  the  sand  together.  If  the 
mixture  is  too  weak  with  clay,  it  will  crumble  when 
compressed  in  the  hand.  When  too  strong,  an  exper- 
ienced mechanic  can  tell  by  the  feeling,  but  no  easy 
method  can  be  pointed  out.  When  the  mixture  is  too 
weak  the  face  of  the  mold  will  crack  or  crumble  easily. 
When  too  strong  or  close  the  casting  will  scab,  as  the 
iron  will  not  lie  quiet  against  it.  The  percent,  of  clay 
determines  its  condition.  The  mixture  giving  the  best 
results  can  only  be  told  when  the  sands  to  be  used 
are  known.  Several  mixtures  are  given  below  which 
give  good  results  at  different  places,  using  the  sands 
available  at  the  particular  place.  These  may  be  taken  as 
general  guides  and  varied  tot  suit  the  sands  used.  The 
clay  wash  generally  consists  of  6  to  8  parts  of  clay  to  I 
of  flour,  wet  with  water  to  the  desired  consistency. 
Receipt  No.  i. — 4  parts  loam  sand,  i  or  2  parts  sharp 

sand,   i  part  dried  horse  manure.     Wet  with  medium 

thick  clay  wash. 
Receipt   No.   2. — 4   parts   molding   sand,    5   parts   sharp 

sand,  1 1/2  parts  dried  horse  manure,  y2  part  dried  and 

sifted  fire  clay,  }A  part  sea  coal.     Wet  with  fair  clay 

wash. 
Receipt  No.  3. — 3  parts  fire  sand,  2  parts  molding  sand,  i 

to  10  parts  horse  manure.    Wet  with  thick  clay  wash. 
Receipt  No.  4. — 4  parts  fire  sand,  i  part  molding  sand, 

i  part  dry  riddled  fire  clay,  i  part  white  pine  sawdust. 

Wet  with  thin  clay  wash. 
Receipt  No.  5. — 2  parts  loam  sand,  2  parts  sharp  sand, 

i   part  old  burned   loam  sand,    i   part  horse  manure. 

Wet  with  thin  clay  wash. 


CHAPTER  V 

There. are  two  types  of  furnace  most  generally  used 
for  remelting  cast  iron  in  the  foundry.  The  reverbera- 
tory  furnace  is  used  in  places  where  soft  grades  of  fuel 
are  plentiful  and  where  special  grades  of  iron  are  neces- 
sary. This  type  will  be  explained  later.  The  cupola  is 
most  generally  used  and  regarded  as  the  most  economical 
furnace. 

Fig.  76  shows  an  elevation  and  section  of  a  New- 
ton cupola  which  illustrates  the  general  type  and  its  con- 
struction. The  shell  is  built  up  of  iron  or  steel  plates  riv- 
eted together.  This  is  lined  with  fire  brick  to  enable  it  to 
withstand  the  heat.  The  lining  is  of  the  same  diameter 
from  the  charging  door  to  the  bottom.  The  bottom  is 
fitted  with  doors  which  cover  the  entire  diameter  of  the 
cupola  so  as  to  allow  a  free  fall  for  the  droppings  at  the 
end  of  each  heat.  On  small  cupolas  up  to  about  30  in. 
in  diameter,  a  single  door  is  used.  In  most  cases  up  to  72 
in.  the  door  is  double,  swinging  from  the  centre  line.  In 
larger  ones  the  door  is  made  in  more  parts. 

The  tapping  hole  or  breast  is  located  above  the  bot- 
tom at  a  height  to  allow  the  sand  covering  to  be  put  upon 
the  bottom  doors  for  holding  the  molten  metal  and  for 
protecting  the  doors  from  the  heat.  The  runner  or  spout 
leads  from  the  breast  to  conduct  the  metal  to  the  receiving 
ladle.  The  tuyeres  are  openings  through  the  lining 
for  the  air  blast  to  enter.  There  may  be  one,  two,  or  three 
rows  of  tuyeres  located  at  different  levels.  The  total  tu 


154 


FOUNDRY  PRACTICE 


Fig.  76. 


FOUNDRY   PRACTICE  155 

yere  area  varies  from  one-tenth  the  cross-sectional  area 
of  the  cupola,  inside  the  lining,  for  small  cupolas,  to  one- 
seventh,  for  those  of  large  diameter.  A  wind-belt,  or 
wind  jacket  surrounds  the  shell  over  the  tuyeres.  The 
blast  is  conducted  to  this  wind  belt  and  enters  the  cupola 
through  the  tuyeres.  Peep  holes  are  provided  in  the 
covering  of  the  wind  jacket  opposite  each  tuyere. 
Through  these  the  melter  may  watch  the  process  of  melt- 
ing. In  the  figure,  a  manometer  is  shown  fastened  to  the 
wind  jacket.  This  indicates  the  pressure  of  the  blast. 
The  amount  of  blast  pressure  varies  with  the  size  of 
cupola.  The  air  must  be  forced  to  the  centre  of  the  fire 
to  effect  combustion  there  at  the  same  rate  as  nearer  the 
lining.  In  small  cupolas  the  pressure  varies  from  4  to  8 
oz.,  while  in  larger  sizes  it  may  be  up  to  14  oz.  per  sq. 
in. 

The  charging  door  is  placed  at  the  charging  floor. 
Its  height  above  the  tapping  hole  or  hearth  of  the  cupola 
should  be  such  as  to  ensure  complete  combustion  of  the 
fuel,  and  absorption  of  the  largest  percentage  of  the  heat 
by  the  charges,  before  passing  the  charging  door. 

The  hearth  is  where  the  molten  metal  accumulates. 
It  is  the  space  between  the  bottom  and  the  level  of  the 
bottom  of  the  tuyeres.  The  average  height  of  the 
hearth  is  about  10  in. 

A  slag  notch  is  provided  on  all  cupolas  for  drawing 
off  the  slag  from  the  surface  of  the  iron  when  running 
long  heats.  The  slag  notch  is  fitted  similarly  to  the  breast 
of  the  cupola  but  at  a  level  slightly  below  the  bottom  of 
the  tuyeres.  It  should  be  so  arranged  that  the  tuyere  is 
not  close  on  either  side,  as  the  cold  air  chills  the  slag 
forming  bridging  or  obstructing  the  tuyere.  In  order 
to  draw  off  the  slag,  the  iron  is  allowed  nearly  to  fill  the 


156  FOUNDRY  PRACTICE 

hearth  up  to  the  slag  notch.  The  notch  is  then  opened 
allowing  the  slag  to  flow  off  the  surface  of  the  iron. 
When  the  iron  appears,  the  slag  notch  is  closed  and  the 
tapping  hole  opened  to  draw  off  the  iron. 

An  alarm  tuyere  or  plugshould  be  provided  on  every 
cupola.  When  the  metal  rises  to  the  bottom  of  the  tu- 
yeres, it  overflows  first  at  the  alarm,  thus  giving  warning 
so  the  metal  is  not  allowed  to  flow  into  the  wind  bell 
and  eventually  fill  it  with  the  iron.  A  common  form  of 
alarm  is  to  have  a  groove  through  the  lowest  tuyere 
which  allows  the  rising  metal  to  flow  off  there  first.  Di- 
rectly below  the  groove  a  plug  is  fitted  having  its  centre 
of  soft  metal  which  is  easily  melted.  The  hot  iron  or 
slag  melts  the  plug,  then  flows  to  the  outside  on  the 
ground  where  it  is  seen.  A  form  which  gives  good  re- 
sults where  the  blast  pressure  does  not  exceed  8  oz.  is  to 
have  a  casting  with  open  centre  and  tapered  flanges  for 
holding  its  cover  fitted  to  the  wind  jacket  below  the 
alarm  tuyere.  The  cover  has  a  small  hole  about  i  in.  in 
diameter  through  its  centre.  About  3  thicknesses  of 
common  paper  are  placed  over  the  cover,  then  slid  into 
place,  thus  making  it  nearly  air-tight,  and  burning 
through  almost  instantly  when  the  cupola  overflows. 
This  form  is  quick  to  replace,  and  acts  more  quickly 
than  most  forms  of  alarm. 

The  lining  of  a  cupola  is  burned  out  more  rapidly  in 
some  parts  than  in  others.  To  allow  renewing  parts  of 
the  lining  without  disturbing  the  entire  brick  work,  angle 
irons  are  riveted  to  the  shell  at  different  levels  to  hold 
the  lining  between  those  levels.  The  brick  may  then  be 
removed  between  any  two  angle  irons  without  disturbing 
the  remainder  of  the  lining. 

In  putting  a  new  lining  into  a  cupola  the  less  clay  that 
can  be  used  between  the  bricks  and  have  the  joints 


FOUNDRY  PRACTICE  157 

sealed,  the  longer  the  lining  will  last.  When  the  clay  is 
thick  in  the  joints,  it  burns  quickly  and  crumbles,  leaving 
the  edges  of  the  bricks  exposed  to  the  fire  thus  burning 
them  away.  The  clay  should  be  mixed  with  water,  and 
very  thin,  so  that  by  dipping  the  bricks  into  the  mixture 
enough  will  adhere  to  form  a  tight  joint.  The  bricks 
should  be  pressed  together  to  squeeze  out  the  superfluous 
clay  and  to  ensure  a  tight  joint. 

The  shell  expands  as  the  temperature  rises,  while  the 
brick  changes  but  slightly.  To  avoid  crushing  the  lining 
when  the  shell  contracts  and  to  maintain  a  tight  lining  as 
the  shell  expands,  a  space  is  left  between  the  shell  and 
the  brick  when  the  lining  is  made.  This  space  is  filled 
with  fine  cinders,  a  mixture  of  fire  clay  and  cinders,  or 
dry  fire  clay.  This  loose  material  protects  the  shell  from 
metal  breaking  through  the  lining,  and  allows  the  shell 
to  give  without  injuring  the  lining. 

The  cupola  must  be  prepared  for  each  succeeding 
heat.  At  the  end  of  each  heat,  when  all  the  iron  has  been 
melted,  the  bottom  is  dropped  to  allow  the  slag  and  ref- 
use to  fall  out.  There  is  always  enough  molten  slag  and 
iron  left  with  the  fuel  to  form  a  solid  mass  if  allowed  to 
cool  in  the  cupola.  Some  of  the  refuse  always  clings  to 
the  lining  so  that  it  does  not  drop  clean.  In  some  cases, 
the  formation  on  the  lining  projects  out  for  some  distance 
or  to  nearly  cover  the  bottom.  Before  another  heat  can 
be  taken  off,  this  refuse  must  be  removed.  This  can  be 
done  with  a  small  pick  or  pinch  bar  having  one  end 
sharpened.  The  thick  parts  are  broken  off  with  a  ham- 
mer, then  the  remainder  with  the  bar.  Care  must  be  tak- 
en to  avoid  loosening  or  injuring  the  brick.  Where  the 
brick  is  glazed  over,  it  should  be  left,  for  that  glazing  is 
as  good  protection  to  the  brick  as  the  clay  daubing. 

After  the  cupola  has  been  picked  out  and  the  lining 


158  FOUNDRY  PRACTICE 

left  clean,  a  coating  of  clay  is  put  over  the  lining.  This 
process  is  called  daubing  the  cupola  and  the  clay  mix- 
ture used  is  called  the  daubing.  The  best  clay  for  this 
purpose  is  fire  clay.  Other  mixtures  are  red  or  blue  clay 
mixed  with  sharp  sand  in  a  proportion  that  will  not  crack 
cpen  when  dry,  or  i  part  of  sand  to  4  cf  clay.  Too  much 
sharp  sand  destroys  the  body  of  the  clay  so  that  it  crum- 
bles. The  fire  clay  is  more  expensive  but  the  lining  will 
last  much  longer  than  when  the  mixture  is  used. 

The  daubing  is  spread  over  the  face  of  the  burned 
lining  to  a  thickness  of  from  l/>  to  I  in.  Where  a  brick 
is  burned  away  deeper  than  the  others,  it  should  be  filled 
in  with  pieces  of  brick  mixed  with  the  clay.  This  keeps 
the  body  of  the  clay  thin  so  it  will  not  crack  or  sag  as 
is  the  case  when  thick  in  places.  When  the  bricks  are 
burned  away  so  that  the  lining  becomes  hollowing,  this 
should  not  be  filled  with  the  clay  to  make  it  even  with 
the  upper  parts.  If  this  is  filled  in,  the  clay  will  sag 
down  and  become  too  heavy  to  stick  to  the  lining.  The 
commotion  of  the  fuel  and  iron  against  it  when  melting 
soon  starts  the  clay  and  makes  it  break  away  from  the 
lining.  This  produces  a  large  amount  of  slag  and  may 
cause  trouble  by  clogging  up  the  cupola  and  stopping  the 
melting.  When  daubing  to  a  thickness  of  l/2  to  I  in.  will 
not  keep  the  shell  from  becoming  red-hot  during  the  heat, 
it  should  be  relined  with  brick. 

After  the  lining  is  prepared  the  bottom  is  made. 
This  consists  of  a  sand  bed  on  the  bottom  door  so  pre- 
pared as  to  hold  the  iron  and  conduct  it  to  the  tapping 
hole.  The  bottom,  or  drop,  door  is  put  up  and  perma- 
nently propped  in  place.  The  sand  is  placed  upon  it 
and  rammed  enough  to  compress  the  surface  to  bear 
the  weight  of  the  iron.  The  bottom  should  slope  back 
from  the  tapping  hole  so  as  to  give  a  free  flow  of  the 
metal  when  tapped  out.  It  should  not  be  sloped  too 


FOUNDRY   PRACTICE  159 

much,  as  that  gives  force  to  the  flow  which  makes  it 
difficult  to  stop,  and  if  not  sloped  enough,  the  iron  may 
freeze  at  the  tapping  hole  when  the  metal  enters  it. 

The  sand  should  be  very  open  and  yet  be  loamy 
enough  to  hold  together  and  not  allow  the  metal  to  ooze 
through  it.  The  sand  may  be  taken  from  the  gangway, 
or  from  the  dirt  pile.  When  too  loamy  it  may  bake  hard 
and  form  a  crust  which  will  not  drop,  especially  in  small 
cupolas.  Very  open  sand  may  be  used,  then  after  the 
bottom  is  shaped  it  may  be  coated  with  clay  wash,  which 
forms  a  firm  crust  on  the  surface. 

Forming  the  tapping  hole  is  an  important  factor  in 
preparing  the  cupola.  The  portion  of  the  cupola  in  front 
of  the  spout  is  called  the  breast.  The  opening  made 
through  the  breast  for  the  iron  to  flow  is  called  the  tap- 
ping hole,  or  port. 

The  brick  work  is  arched  over  the  breast,  leaving  an 
opening  for  forming  the  tapping  hole  of  the  desired 
depth.  For  the  remaining  distance  between  the  inner 
edge  of  the  tapping  hole  and  the  face  of  the  brick  the 
form  is  cone-shaped  of  such  a  pitch  that  it  enlarges  rap- 
idly toward  the  inside.  The  tapping  hole  should  not  be 
more  than  3  in.  long.  The  front  may  be  put  in  before 
putting  in  the  fuel  for  the  bed,  or  afterwards  by  using 
the  fuel  for  a  backing  to  form  it  against.  When  the  cu- 
pola is  large  enough,  a  good  plan  is  to  place  a  board 
against  the  lining  to  cover  the  breast,  put  the  draw-plug  in 
the  desired  position  for  the  tapping  hole,  and  ram  or  pack 
the  breast  into  the  desired  shape.  The  plug  and  board 
are  removed,  then  the  inside  is  shaped  with  a  trowel  even 
with  the  brick  and  a  conical  hole  to  within  3  in.  of  the 
outside  to  form  the  tapping  hole.  The  breast  may  be 
made  of  a  mixture  of  clay  and  new  molding  sand  or  ? 
stiff  clay.  It  is  best  to  form  the  bottom  of  clay  for  4  or 


i6o 


FOUNDRY  PRACTICE 


Fig.  76.  A. 


FOUNDRY  PRACTICE  161 

5  in.  in  front  of  the  tapping  hole,  to  prevent  the  tapping 
bar  from  making  a  hole  in  the  bottom. 

The  spout  should  be  lined  with  clay  when  the  breast 
is  put  in.  It  is  partly  dried  with  charcoal  or  with  wood 
before  the  fuel  is  charged  into  the  cupola. 

After  the  cupola  is  prepared  for  charging,  the  kind- 
ling for  starting  the  fire  is  placed  upon  the  bottom. 
Shavings  are  placed  in  front  of  the  breast  for  lighting 
and  the  wood  on  top  of  them.  A  sufficient  amount  of 
wood  is  put  upon  the  kindling  to  ensure  its  starting  the 
coke  to  a  good  fire.  Coke  is  placed  upon  the  wood  to  the 
amount  of  the  bed  charge.  It  is  then  ready  to  light.  Iron 
should  not  be  charged  until  the  coke  begins  to  burn  or 
until  fire  shows  through  at  the  top  of  the  bed.  Iron  and 
coke  should  be  charged  successively  until  it  is  at  the 
height  of  the  charging  door.  Succeeding  charges  are 
put  in  as  fast  as  the  previous  charges  settle  away  from 
the  charging  door.  The  charge  within  the  cupola  is  kept 
to  the  height  of  charging  door  until  the  entire  amount  to 
be  charged  has  been  put  in.  This  is  so  that  the  descend- 
ing charge  may  take  up  as  much  of  the  heat  of  the  escap- 
ing gases  as  possible,  so  that  the  iron  may  be  near  the 
melting  point  when  it  descends  to  the  melting  zone.  The 
charge  of  coke  on  the  bed  must  be  of  an  amount  that  will 
hold  the  iron  at  the  melting  zone  of  the  cupola  until  it  is 
all  melted.  Each  succeeding  charge  should  be  of  the 
amount  necessary  to  melt  the  charge  of  iron  placed  upon 
it.  The  first  charge  of  iron  may  be  much  larger  than  the 
succeeding  charges,  but  must  not  be  so  large  that  part  of 
it  passes  below  the  melting  zone  before  it  is  melted. 

The  weights  of  the  charges  for  a  26  in.  cupola  are 
given  below : 
On  first  charge,  390  pounds  of  coke  on  bed,  1,170  pounds 


162  FOUNDRY  PRACTICE 

of  iron.     On  each   succeeding  charge,   50  pounds   of 
coke,  alternating  with  450  pounds  of  iron. 

The  smallest  heat  that  may  be  taken  from  a  cupola 
consists  of  the  bed  charge  and  one  succeeding  charge. 
The  largest  heat  is  that  which  may  be  run  off  before  the 
tuyeres  become  clogged  so  that  the  melting  stops.  For 
long  heats,  a  flux  should  be  charged  with  the  iron,  which 
forms  a  slag  of  the  refuse  in  the  cupola  and  makes  the 
slag  more  fluid.  The  slag  is  removed  through  the  slag 
notch,  which  clears  the  cupola,  allowing  it  to  run  long- 
er without  stopping  up. 

In  order  to  produce  a  soft  iron  for  machinery  cast-- 
ings, mix  I  part  of  soft  foundry  pig  iron  with  4  parts 
of  machinery  scrap  iron. 

In  using  limestone,  marble,  or  shells,  the  flux  is 
charged  with  the  iron  in  an  amount  of  30  to  50  Ibs.  to 
one  ton  of  iron. 

The  tapping  out  and  stopping  up  of  a  cupola  must 
be  accomplished  while  the  blast  is  on.  After  the  fire  is 
lighted  the  breast  or  port  hole  and  the  covers  over  the 
tuyeres  are  left  open  to  supply  air  to  the  fire  until  the 
blast  is  turned  on.  The  fire  should  be  started  early 
enough  to  allow  the  wood  to  burn  out  and  the  coke  to 
become,  well  ignited  before  the  blast  is  turned  on.  As  the 
blast  is  started,  the  covers  over  the  tuyeres  are  closed, 
leaving  only  the  port  hole  open.  This  is  kept  open  until 
the  molten  metal  appears,  when  it  is  closed  with  a  clay 
ball.  The  blast  is  allowed  to  blow  through  the  port  so  as 
to  burn  the  coke  lodged  in  it  and  ensure  a  free  pas- 
sage for  the  first  tap.  After  the  metal  appears  it  will 
keep  the  coke  and  refuse  out  of  the  tapping  hole.  The 
fire  blowing  through  the  port  heats  it  to  prevent  the  chill- 
ing of  the  first  iron  that  enters  it. 


FOUNDRY  PRACTICE  163 

The  tools  used  for  tapping  and  stopping  up  a  cupola 
are  shown  in  Fig.  77.  The  bott  stick  is  for  stopping  up 
the  cupola  by  placing  a  clay  ball  upon  the  disk  end  to 
close  the  port.  The  tapping  bar  is  used  for  tapping  out 
or  removing  the  clay  ball  which  has  become  baked  in  the 
port.  The  tapping  chisel  is  used  when  iron  or  encrusta- 
tions have  frozen  about  the  tapping  hole  so  that  the  bar 
can  not  remove  them. 

In  stopping  up  the  cupola,  the  bott  stick  should  be 
directed  downward  into  the  port,  so  that  the  clay  is 
pressed  into  the  hole  before  it  dries  on  the  face  by  contact 


BOTT  STICK 


TAPPINQ-BAR 


TAPPING-CHISEL 

Fig.  77- 

with  the  metal.  When  the  bott  stick  is  forced  against  the 
stream  of  metal,  it  washes  away  or  forms  a  crust  which 
will  not  unite  with  the  edges  of  the  hole,  therefore  it  will 
not  stop  the  flow.  The  clay  ball  must  hold  the  pressure 
of  the  blast  and  that  of  the  metal  head  acting  against  it. 
Where  long  bott  sticks  are  necessary,  a  light  and  stiff 
one  may  be  made  of  a  tube  whose  ends  are  drawn  so 
that  a  handle  is  welded  at  one  end  and  a  rod  bearing  the 
disk  at  the  other.  A  soft  wood  bott  stick  having  a  metal 
end  on  which  to  place  the  ball  gives  good  service  and  is 
light  to  handle. 


1 64 


FOUNDRY  PRACTICE 


The  clay  for  stopping  a  cupola  must  be  capable  of 
bearing  the  pressure  and  still  not  bake  so  hard  that  it  can 
not  be  broken  away  with  the  tapping  bar.  A  mixture  for 
forming  the  clay  balls  is  i  part  sand  to  3  parts  of  good 
clay,  then  I  part  flour  to  10  parts  of  the  mixture.  This 
will  bake  as  a  core  for  holding  the  metal  and  after  drying 
it  crumbles  away  easily  before  the  tapping  bar. 


Fig.  78. 

Furnaces  of  the  reverberatory  type  are  now  used 
only  where  it  is  important  to  have  the  iron  of  a  par- 
ticular quality  or  chemical  combination.  For  chilled 
work  and  castings  for  malleableizing,  the  reverberatory 
furnace  has  some  advantage  over  the  cupola.  The  fuel 
required  for  melting  a  given  amount  is  about  double 


FOUNDRY  PRACTICE 


165 


that  of  a  cupola.    Soft  and  cheaper  fuels  may  be  used. 

In  this  furnace  the  fuel  is  burned  upon  a  grate  and 
the  metal  is  held  in  a  separate  division  where  it  is  not  in 
contact  with  the  fuel.  The  process  of  melting  is  slower, 
and  the  molten  metal  may  be  retained  in  the  furnace  until 
its'  chemical  condition  is  that  desired.  Test  may  be  made 
of  the  accumulated  metal,  and  when  the  carbon  is  in  the 
proper  condition  the  metal  may  be  tapped  out  and  cast. 

The  two  general  forms  of  furnace  are  shown  in  Figs. 
78  and  79.  In  the  furnace  represented  by  Fig.  78,  the 
bath  is  immediately  behind  the  bridge,  while  that  shown 


Fig.  79. 

in  Fig.  79  has  its  bath  at  the  end  remote  from  the  bridge 
The  fuel  is  placed  upon  the  grates  through  the  opening 
G.  The  charging  door  is  shown  at  D,  which  is  a  cast 
iron  door  lined  with  fire  brick.  The  hearth  at  H  is  where 
the  metal  is  placed  when  charged.  O  shows  the  opening 
or  peep  holes  through  which  the  process  of  melting  may 
be  seen  or  the  working  of  the  metal  effected.  The  tap- 
ping hole  is  shown  at  T  at  the  bottom  of  the  bath. 

The  bed  or  bottom  of  the  furnace  is  made  similar  to 
that  of  a  cupola,  using  the  same  mixture  or  one  that  is 


166  FOUNDRY  PRACTICE 

more  open.  This  bed  will  last  for  eight  to  ten  heats,  if 
it  has  been  well  dried  before  the  first  charge  is  placed 
upon  it.  The  walls  and  roo>f  of  the  furnace  are  made  of 
the  most  refractory  kind  of  fire  brick,  using  care  to  have 
close  joints  and  all  crevices  carefully  sealed  to  ensure 
proper  working  of  the  furnace. 

When  iron  is  in  a  molten  state,  the  presence  of  oxy- 
gen will  affect  the  carbon  in  the  iron  and  burn  out  the 
graphitic  carbon,  making  it  harder  and  more  brittle.  The 
special  object  of  using  a  reverberatory  furnace  is  to  ob- 
tain an  iron  having  its  carbon  in  the  form  desired,  hence 
it  is  very  important  that  cold  air  or  oxygen  should  not 
strike  upon  the  metal.  The  openings  must  be  closed  ex- 
cept when  necessary  to  assist  the  working  of  the  furnace. 
The  entire  charge  for  the  heat  must  be  placed  upon  the 
hearth  before  melting  begins,  because  the  furnace  is  so 
cooled  and  the  metal  acted  upon  by  the  cold  air  when  a 
new  charge  is  put  in  that  it  can  not  be  brought  back  and 
the  charge  melted  before  the  iron  in  the  bath  is  too  cold 
for  use.  It  is  similarly  of  importance  that  an  even  fire 
should  be  maintained  and  that  no  holes  be  caused  h\ 
cleaning  or  raking  the  fire,  thus  avoiding  the  entrance  of 
air  to  the  furnace  through  the  fire.  The  pressure  of  the 
blast  should  be  that  necessary  to  maintain  a  rapid  fire 
with  complete  combustion.  The  usual  pressure  necessary 
is  from  6  in.  to  7  in.  of  water  column. 

The  iron  should  be  charged  onto  the  hearth  so  as  to 
leave  openings  between  the  pieces.  The  first  layer  should 
extend  lengthwise  of  the  furnace  and  each  succeeding 
one  should  lie  across  the  preceding  layer.  The  melter 
may  often  hasten  the  process  of  melting  by  separating 
the  pieces  or  by  breaking  apart  those  that  tend  to  weld. 
The  molten  metal  is  skimmed,  as  the  accumulation  of 


FOUNDRY  PRACTICE  167 

dirt  or  scum  shields  the  surface  from  the  direct  action  of 
the  flames  and  thus  the  furnace  loses  its  efficiency.  When 
various  brands  of  iron  are  charged  into  the  furnace,  the 
metal  is  mixed  by  the  process  of  "boiling,"  or  "polling 
the  metal."  This  process  usually  consists  of  thrusting 
green  wood  into  the  metal,  causing  a  violent  ebullition 


Fig.  80. 

throughout  the  mass,  ensuring  a  homogeneous  product. 
After  all  the  charge  is  melted  and  the  iron  is  white-hot, 
the  melter  dips  a  sample  from  the  furnace  with  a  small 
hand  ladle  for  testing.  If  found  satisfactory,  the  mass 
is  boiled  or  polled  for  about  five  minutes,  then  the  damp- 
er in  the  flue  is  closed  and  the  furnace  tapped.  The  iron 


Fig,  81 . 

should  then  be  poured  immediately,  as  it  will  change  in 
the  ladles.  All  the  operations  in  the  furnace  are  con- 
ducted through  the  openings  or  peep  holes,  and  are  per- 
formed as  quickly  as  possible  to  avoid  keeping  the  holes 
open  longer  than  absolutely  necessary. 


i68 


FOUNDRY  PRACTICE 


Fig.  82. 

The  vessels  in  which  the  molten  iron  is  handled  arc 
called  ladles.  They  are  generally  divided  into  four 
classes.  Hand  ladles  shown  in  Fig.  80  are  handled  by 


Fig.  83. 

one  man  and  hold  up  to  50  Ibs.  of  iron.    The  bull  ladles 
are  those  having  a  double  shank  and  are  carried  by 


FOUNDRY  PRACTICE  169 

two  or  more  men.  Such  a  ladle  is  shown  is  Fig.  81 
with  the  bail  removed,  or  similarly  in  Fig.  no,  having 
the  straight  shank  on  one  side.  These  ladles  hold  from 
75  to  35°  Ibs.  of  iron.  The  crane  ladles  are  all  those 
handled  by  use  of  the  crane.  There  are  two  general 
types,  those  having  the  fixed  shank  with  bail,  as  in 
Fig.  81,  and  those  having  the  gearing,  as  in  Fig.  82. 
The  fourth  type  of  ladle  is  used  only  in  special  places 
where  suited  for  such  use.  These  are  mounted  on 
wheels  and  are  known  as  truck  or  car  ladles,  as  shown 
in  Fig.  83.  They  are  used  for  delivering  the  iron  from 


Fig.  84. 

the  cupola  to  a  crane  ladle  or  to  the  floors  where  it  is 
to  be  poured. 

The  ladle  is  made  of  sheet  iron  riveted  together,  and 
must  be  lined  with  clay  or  fire  brick  to  withstand  the 
heat.  The  clay  used  may  be  about  i  part  sharp  sand  to  4 
parts  pure  clay.  When  the  clay  itself  contains  sand,  the 
sharp  sand  may  be  reduced.  The  lining  is  put  on  evenly 
from  Y-2  to  34  in.  thick  and  dried.  The  cracks  are  filled 
with  thin  clay  and  again  dried  to  ensure  a  solid  surface. 
The  large  ladles,  as  for  the  crane,  are  lined  with  fire 
brick  laid  up  in  fire  clay,  as  in  the  case  of  the  cupola  lin- 


170 


FOUNDRY  PRACTICE 


ing".  A  daubing  of  clay  is  placed  over  the  fire  brick  to 
take  the  cutting  and  wash  of  the  iron.  The  daubing  is 
put  on  the  same  as  the  lining  of  the  smaller  ladles.  In 
receiving  ladles  for  the  cupola,  the  continual  fall  of  the 
iron  upon  one  point  as  it  comes  from  the  spout  cuts  away 
the  lining  very  rapidly.  Without  special  protection  the 
lining  will  be  cut  away  in  a  comparatively  short  time.  A 


Fig.  85- 

good  method  of  daubing  this  ladle  is  to  have  the  place 
where  the  metal  strikes  built  up  with  small  pieces  of  fire 
brick  laid  into  the  clay  very  closely,  and  the  mass  well 
bound  together  with  the  clay  daubing  and  thoroughly 
dried  before  the  metal  strikes  it. 

The  blast  for  melting  the  iron  is  produced  by  blow- 
ers suitable  to  deliver  the  volume  of  air  desired  and  to 
maintain  the  pressure  required  for  the  particular  fur- 
nace. There  are  two  types  of  blower  in  general  use : 
first,  the  positive  blast  or  root  blower,  and  second,  the 
fan. 


FOUNDRY  PRACTICE 


171 


Fig.  86. 


i?2  FOUNDRY  PRACTICE 

Fig.  84  illustrates  one  style  of  a  root  blower  which 
is  driven  by  a  belt.  The  blast  is  produced  by  the  rotation 
of  the  vanes  as  indicated  by  the  arrows  shown  in  the 
sectional  view  in  Fig.  85.  These  blowers  are  positive,  be- 
cause the  volume  of  air  delivered  at  the  discharge  side 
can  not  escape  back  between  the  vanes  to  the  admitting 
side,  even  if  the  pressure  is  increased  in  the  discharge 
pipe.  A  relief  valve  is  usually  placed  on  the  discharge 
pipe  which  relieves  excess  pressures. 

Fig.  86  shows  one  form  of  fan  blower  which  is  driven 
by  belt.  The  blast  is  produced  in  these  by  the  centrifugal 
force  given  the  air  at  the  end  of  the  vanes  and  acting 
tangentially  to  the  rotation  of  the  fan,  thus  discharging 
into  the  delivery  pipe.  The  air  supply  is  taken  in  at  the 
centre  which  is  left  open.  When  the  pressure  in  the  de- 
livery pipe  becomes  equal  to  the  centrifugal  force  pro- 
duced by  the  fan,  the  air  will  not  be  delivered  into  the 
discharge  pipe,  hence  no  further  increase  of  pressure. 

Either  of  these  blowers  may  be  directly  connected  or 
may  be  driven  by  ropes  or  belts. 


CHAPTER  VI 

In  many  castings  it  is  desirable  that  parts  of  the  sur- 
face shall  be  very  hard,  to  withstand  wear  and  tear* 
while  other  parts  shall  retain  its  general  toughness  or 
shall  be  of  soft  iron.  This  result  is  effected  by  chilling 
the  portion  of  casting  desired  to  be  hard.  The  chilling 
is  accomplished  by  placing  an  iron  chill  in  the  mold 
where  chilling  is  desired,  while  the  other  portions  of  the 
mold  are  formed  of  sand  as  usual.  The  metal  coming  in 
contact  with  the  iron  is  cooled  quickly  and  holds  the  car- 
bon in  the  combined  or  white  iron  form,  while  the  parts 
cooling  more  slowly  allow  the  carbon  to  change  back  to 
the  graphitic  or  gray  iron  form,  which  is  soft  and  tough. 

This  method  of  hardening  parts  of  castings  is  used 
for  many  forms  of  casting  and  under  various  conditions. 
The  most  extensive  use  is  that  of  chilling  the  rim  of  car 
wheels  and  the  face  of  rolls. 

The  sand  parts  of  the  mold  are  made  similar  to  other 
castings,  either  in  green  or  dry  sand  as  the  case  may  re- 
quire. The  chill  portions  are  placed  into  the  mold  as  a 
third  part  to  the  flask,  as  in  car  wheels  and  rolls,  or  are 
set  similarly  to  a  core  in  the  side  of  small  molds,  as  ma- 
chine parts,  anvils,  etc.  The  chill  is  heated  in  an  oven 
to  a  temperature  of  about  200°  F.,  before  placing  in  the 
mold.  The  moisture  from  the  mold  and  from  the  sand 
adjoining  the  chill  would  be  deposited  on  the  surface  if  it 
were  cold,  thus  causing  it  to  blow  and  to  force  the  molten 
iron  away  from  it  when  cast.  After  warming,  the  face  of 


174  FOUNDRY  PRACTICE 

the  -chill  must  be  coated  in  order  to  prevent  the  iron  from 
sticking  to  the  surface  and  to  allow  the  chill  to  be  lifted 
from  the  surface.  A  coating  of  blacking  wet  with  mo- 
lasses water  gives  good  satisfaction.  Other  methods  of 
coating  that  work  better  in  particular  cases  are :  to  shellac 
the  face  and  allow  to>  harden  well  before  using;  to  var- 
nish the  face  with  a  common  grade  and  when  nearly  dry 
sprinkle  with  plumbago ;  or  to  use  a  thin  coating  of  a 
light  clean  oil,  as  a  heavy  oil  or  a  thick  coat  will  burn 
O'ff,  thus  holding  the  iron  away  by  the  gases  formed. 

The  chill  should  be  so-  placed  in  the  mold  that  the 
metal  shall  rise  on  the  chill  but  shall  not  lie  horizontally 
or  have  the  inflowing  metal  fall  upon  the  chill.  The 
gates  should  be  so  arranged  and  of  such  a  size  that  the 
chill  will  be  covered  quickly  to  prevent  the  metal  form- 
ing bubbles  on  the  surface  of  the  chill.  It  should  be 
flushed  up  quickly,  or  the  chill  will  cause  cold-shots  and 
streaks  in  the  chill  surface. 

The  metal  in  contact  with  the  chill  forms  a  crust  or 
shell  quickly  and  contracts,  holding  the  remainder  of  the 
iron  while  still  in  the  molten  state.  If  there  is  any  un- 
evenness  in  the  pressure  on  this  shell,  it  may  caus? 
cracking  or  bursting  of  the  surface,  as  is  sometimes  not  - 
ed  in  chilled  faces.  This  may  be  lessened  by  having  the 
flask  so  arranged  that  the  chill  is  level,  as  in  rolls  or  car 
wheels. 

The  chill  should  be  made  of  the  best  grade  of  iron 
having  little  contraction;  so  that  the  surface  will  not 
check  and  bre?k  when  the  face  is  suddenly  heated  by  tn? 
molten  metal.  A  good  iron  for  making  chill  casting  will 
make  a  good  chill.  Wrought  iron  is  sometimes  used  for 
a  chill.  The  thickness  of  the  chill  is  much  depended 
upon  the  depth  that  it  is  desired  to  chill  the  casting.  It 


FOUNDRY  PRACTICE  175 

must  be  of  such  a  size  that  it  may  conduct  away  the  heat 
necessary  to  cool  the  iron  from  the  molten  state,  about 
2,500°  F.,  to  that  of  solidification,  at  out  1,000°  F.,  and 
must  hold  it  at  that  temperature  so  that  the  iron  within 
will  not  remelt  the  chilled  skin.  Special  types  of  chill 
for  car  wheels  are  in  use  which  give  good  results.  They 
are  made  up  of  parts  instead  of  a  solid  ring,  and  some 
forms  are  so  arranged  that  the  chill  contracts  as  the  cast- 
ing contracts,  thus  following  the  surface  of  the  casting  as 
it  cools.  Another  form  has  open  chambers  through 
which  steam  is  circulated  to  warm  the  chill  before  cast- 
ing, then  cold  water  is  circulated  after  casting,  to  effect  a 
deeper  chill.  The  depth  of  chill  is  dependent  upon  the 
mixture  of  iron  used  and  the  rapidity  with  which  the  face 
of  the  casting  is  cooled.  The  depth  of  chill  on  rolls  var- 
ies from  Jo  in.  to  J/&  in.  to  suit  different  requirements. 
Some  users  of  rolls  desire  a  defined  chilled  skin  while 
others  wish  the  chilled  portion  to  shade  gradually  into-  the 
soft  interior  of  the  casting.  Car  wheels  are  chilled  to  a 
depth  of  about  24  m- 

The  mixtures  of  iron  for  chill  castings  can  be  success- 
fully made  only  by  use  of  chemical  analysis,  and  not  by 
judging  from  the  fracture.  Good,  soft  iron  should  have 
1.8  per  cent,  silicon;  while  this  will  not  chill  without  ex- 
cess of  sulphur,  which  makes  a  very  poor  iron.  Chill 
iron  should  have  less  than  i  per  cent,  silicon  and  not 
over  0.08  per  cent,  sulphur.  The  total  carbon  should  be 
as  high  as  possible,  other  metalloids  being  constant.  The 
combined  or  hardening  carbon  should  rarely  exceed  0.6 
per  cent.,  as  that  makes  the  iron  too  hard  and  too  brittle. 
The  mixtures  must  be  closely  watched  and  tested  every  day 
to  ensure  the  proper  proportion  of  impurities.  Iron  melt- 
ed in  a  cupola  is  tested  before  pouring  into  the  chill 


i;6  FOUNDRY  PRACTICE 

molds.  The  test  is  for  depth  cf  chill,  and  the  test  bar  is 
about  2  in.  square  and  6  in.  long,  having  one  side  against 
a  chill.  It  is  cooled  and  broken,  and  if  the  chill  is  insuf- 
ficient it  is  poured  into  other  molds  or  pig  beds  where  it 
may  be  remelted.  The  air  or  reverberatory  furnace  has 
many  advantages  for  this  class  of  work,  as  the  iron  may 
be  tested  and  varied  by  addition  of  special  irons  before 
tapping  for  the  purpose  of  pouring. 


CHAPTER  VII 

Malleable  cast  iron  is  a  form  that  becomes  tough  and 
partly  malleable  when  annealed  by  the  malleableizing  pro- 
cess. The  iron  loses  its  brittleness  and  may  be  bent  or 
straightened  without  breaking.  Thus  it  may  better  re- 
sist shock  and  occupies  a  place  between  gray  iron  and 
wrought  iron,  having  a  higher  tensile  strength  than  the 
former  and  less  ductility  than  the  letter. 

The  effect  of  the  malleableizing  process  is  to  change 
the  chemical  compcsition  of  the  iron  by  action  on  the 
metalloids.  The  total  carbon  is  reduced,  making  the  out- 
er part  nearly  a  wrought  iron.  T!  e  carbon  remaining  is 
changed  from  the  hardening,  or  combined  carbon,  to 
graphitic  that  of  gray  iron.  The  percentages  of  silicon, 
manganese  and  phosphorus  are  also  changed. 

The  iron  used  must  be  a  white  iion  whose  carbon  will 
be  in  the  combined  form.  The  per  cent,  of  silicon  must 
be  low,  because  it  tends  to  eliminate  the  carbon.  When 
above  0.75  per  cent.,  the  metal  will  have  a  high  tensile 
strength  but  small  eloTgaticn.  The  rracture  has  a  steely 
appearance  in  the  finished  casting*  when  the  silicon  is  too 
high.  Phosphorus  is  beneficial  up  to  0.15  per  cent.,  as  it 
helps  maintain  fluidity  in  the  metal.  Sulphur  is  very  det- 
rimental when  present  in  appreciable  percentages.  An 
iron  having  sulphur  or  phosphorus  tco  high  will  be  hard- 
er and  have  cracks  at  the  surface  of  the  casting.  The 
presence  of  manganese  in  comparatively  high  percent- 
ages is  beneficial  to  the  resulting  casting.  It  acts  as  a 


i;8  FOUNDRY  PRACTICE 

neutralizer  on  the  silicon  to  prevent  its  effect  upon  the 
carbon  as  the  carbon  changes  its  state.  Manganese  assists 
the  carbon  change,  and  shortens  the  time  necessary  for 
its  completion.  Scaly  castings,  when  properly  packed, 
result  from  too  low  a  percentage  of  manganese. 

The  process  of  annealing  is  effected  by  packing  the 
boxes.  They  are  placed  in  ovens  which  are  sealed  and 
castings  with  oxidizing  reagents  info  covered  cast  iron 
heated  by  some  form  of  d'rect  fired  furnace  which  holds 
the  temperature  uniformly  at  about  1,850°  F.  for  a  peri- 
od from  eight  hours  to  several  days,  dependent  upon  the 
size  and  character  of  the  castings.  The  ovens  are  so  ar- 
ranged as  to  distribute  the  heat  eve  nly  and  not  to  be  sub- 
jected to  sudden  changes.  The  temperature  is  measured 
by  a  pyrometer  which  will  indicate  the  high  temperature. 
Too  high  or  too  low -a  temperature  affects  the  action  of 
the  reagents  and  injures  the  resulting  castings.  The 
oven  is  heated  slowly  so  as  to  maintain  the  temperature 
of  the  castings  at  nearly  that  of  the  oven  at  all  times,  and 
is  cooled  very  slowly  when  the  process  is  complete,  to 
avoid  a  chemical  change  due  to  the  sudden  change  of 
temperature.  These  ovens  may  be  fired  by  coke,  coal, 
oil,  or  gas. 

The  reagents  used  must  be  high  in  oxygen,  which  at 
the  temperature  of  the  annealing  will  combine  with  the 
carbon  of  the  iron  forming  CO  gas,  which  passes  off. 
Some  of  the  reagents  used  are  red  hematite  ore,  rolling 
mill  scale  well  oxidized  or  rusted,  and  steel  turnings 
heavily  rusted.  The  oxidizing  may  be  effected  by  a  weak 
solution  of  sal-ammoniac.  These  may  be  used  several 
times  by  the  addition  of  a  partly  fresh  unburnt  reagent, 
or  by  reoxidizing  with  sal-ammoniac  each  time.  The 
casting  must  be  completely  covered  with  the  reagent 


FOUNDRY  PRACTICE  179 

when  packed  in  the  boxes.  If  two  castings  touch,  those 
spots  will  not  be  properly  malleableized,  thus  making  an 
imperfect  casting. 

The  form  and  proportions  of  the  pattern  for  malleable 
work  require  special  attention.  Sharp  angles  must  be 
avoided  and  all  corners  filleted  with  adequate  radii.  The 
iron  always  shrinks  away  from  the  angle  in  both  direc- 
tions, thus  causing  a  crack  or  depression,  which  should 
be  avoided.  The  change  from  light  to  heavy  section 
should  be  gradual.  The  round  section  has  proved  to  be 
the  weakest  form,  hence  it  should  be  avoided.  As  the 
greatest  strength  of  malleable  castings  lies  in  the  skin, 
it  is  preferable  to  have  as  great  a  surface  as  possible 
with  no  great  thickness  of  metal,  as  in  many  cases  it  is 
preferable  to  have  several  thin  ribs  rather  than  one  thick 
one. 

The  gating  of  castings  to  be  maileableized  is  of  great 
importance  and  requires  the  most  skill  and  experience  of 
any  part  of  the  work.  For  this  reason  most  patterns  have 
gates  attached  which  are  put  on  by  experienced  men. 
The  cause  of  difficulty  in  gating  a  casting  or  running  in- 
tricate forms,  as  in  gray  iron,  is  the  hardness  of  the  iron, 
causing  it  to  shrink  more  and  set  more  quickly.  The 
branch  gate  should  not  extend  from  the  bottom  of  the 
feeder,  as  it  will  chill  from  the  sand,  thus  solidifying 
sooner  than  the  metal  in  the  mold.  The  feeder  should 
extend  about  one-third  its  length  below  the  branch  gate 
and  should  be  as  close  as  possible  to  the  casting.  For 
light  patterns  the  branch  gate  should  not  exceed  J/£  in. 
in  length,  and  it  is  '  preferably  of  circular  section. 
When  it  is  difficult  to  feed  a  portion  of  a  mold  properly, 
a  chill  may  be  placed  at  that  point  to  solidify  it  more 
quickly  than  the  other  parts,  thus  preventing  fracture  or 
shrink-holes. 


CHAPTER  VIII 

When  the  casting  comes  from  the  mold  it  has  more  or 
less  sand  adhering  to  its  surface,  or  the  cores  are  still  in 
the  casting.  It  must  be  cleaned  and  all  sand  removed 
before  it  is  ready  for  the  machine  shop.  The  gates  and 
risers,  as  well  as  all  fins,  should  be  chipped  off.  This  is 
a  portion  of  the  cleaning  and  of  the  preparation  for  leav- 


Fig.  87. 

ing  the  foundry.  The  methods  of  cleaning  the  sand  from 
castings  may  be  classed  under  three  main  heads  :  First,  the 
use  of  tumbling  barrels ;  second,  hand  work ;  third,  the 
use  of  pneumatic  appliances.  The  tumbling  barrel,  or 
rattler,  is  driven  by  power  and  cleans  the  castings  by 


FOUNDRY  PRACTICE 


181 


their  rolling  about  in  the  drum  as  it  turns  over.  Fig. 
87  represents  a  tumbling  barrel  driven  by  the  friction 
wheels  on  which  it  rests.  Fig.  88  shows  a  pair  of 


tumbling  barrels  driven  by  gears  and  having  the  ex- 
haust connection  for  drawing  away  the  dust  as  it  is 
freed  from  the  castings. 

The  cleaning  by  hand  is  chiefly  done  by  use  of  wire 


182 


FOUNDRY  PRACTICE 


brushes  and  emery  bricks,  or  rub-stones.  When  the  sand 
is  fused  hard  onto  the  casting,  it  may  reqiiire  chipping, 
filing,  or  scraping  with  iron  scrapers.  The  use  of  pneu- 
matic appliances  for  foundry  work  is  increasing  rapidly. 


The  greatest  convenience  for  cleaning  is  found  in  the 
sand  blast  appliances  as  represented  in  Fig.  89,  also  as 
connected  to  a  tumbling  barrel  having  an  exhaust  con- 
nection. The  sand  blast  is  attached  to  the  tumbling  bar- 


FOUNDRY  PRACTICE  183 

rel  at  the  centre  opposite  to  the  exhaust  pipe.  This  gives 
the  action  of  the  sand  blast  upon  the  castings  as  they 
move  about  in  the  tumbling  barrel. 

The  gates,  risers,  and  fins  on  castings  are  removed,  in 
general,  by  hand  chipping,  or  by  the  use  of  a  pneumatic 
hammer  shown  in  Fig.  94.  When  the  gates  on  castings 
can  not  be  broken  and  chipped  without  danger  of  break- 
ing into  the  casting,  it  is  sawed  off  or  ground  off  on.  an 
emery  wheel.  Many  shops  are  equipped  with  cold  saws 
for  this  purpose.  All  shops  making  steel  castings  must 
be  provided  with  cold  saws  of  some  type,  because  the 
gates  and  risers  must  be  so  large  that  it  is  impossible  to 
chip  them  off  without  danger  of  spoiling  the  casting.  The 
emery  wheel  is  used  extensively  on  small  castings  and  for 
smoothing  over  the  chipping  on  other  castings.  The  fixed 
wheel  of  a  coarse  grade  is  generally 'used.  The  portable 
emery  wheel,  or  grinder,  is  very  convenient  for  large 
castings. 


1 84 


FOUNDRY  PRACTICE 


CHAPTER  IX 

The  use  of  compressed  air  in  a  modern  foundry  is 
considered  indispensable.  By  use  of  pneumatic  tools  and 
machinery  the  cost  of  foundry  products  is  greatly  re- 
duced. The  appliances  operated  by  compressed  air  are 
the  pneumatic  crane,  hoist,  molding  machine,  sand  sifter, 
chipping  hammer,  screen  shaker,  sand  rammer,  and  sand 
blast  machine. 

The  pneumatic  crane  is  shown  in  Fig.  90.  All  move- 
ments of  the  crane  are  controlled  by  the  operator  on  the 
carnage. 

The  pneumatic  hoist  is  shown  in  Fig.  91.  In  lifting 
copes  and  drawing  patterns,  the  most  perfect  and  regular 
motion  is  required  to  prevent  "sticks,"  "tears,"  and  "drop- 
outs."  A  jerk  is  fatal  to  the  mold.  This  hoist  may  be 
moved  with  a  speed  as  slow  and  as  regular  as  the  hour 
hand  of  a  clock,  and  a  change  of  speed  may  be  made 
without  a  sudden  jerk  or  jar.  It  may  be  operated  rapid- 
ly as  well. 

A  pneumatic  molding  machine  is  shown  in  Fig.  92. 

The  pneumatic  sand  sifter  is  shown  in  Fig.  93.  This 
machine  is  operated  by  an  air  cylinder  directly  connect- 
ed to  the  sifter.  The  air  is  supplied  to  the  cylinder  by  a 
rubber  hose,  making  the  machine  portable  so  that  it  may 
be  used  in  any  location  in  the  foundry. 

The  pneumatic  chipping  hammer  is  shown  in  Fig. 

94- 

The  pneumatic  sand  rammer  in  Fig.  95  is  fitted  to 


i86 


FOUNDRY  "PRACTICE 


Fig.  91. 


FOUNDRY  PRACTICE 


187 


Fig.  92. 


i88 


FOUNDRY  PRACTICE 


hang  from  a  support,  and  has  both  pein  and  butt  as  the 
operator  may  desire. 

The  sand  blast  machine  is  shown  in  Fig.  89. 


Fig.  93- 


Fig.  96  shows  a  pneumatic  shaker  mounted  on  a 
tripod  so  that  it  may  be  placed  wherever  desired  and  may 


Fig.  94- 


FOUNDRY   PRACTICE 


189 


be  fitted  to  hold  a  riddle,  so  that  a  riddle  of  any  desired 
number  may  be  placed  in  it.  » 

Fig.  97  represents  a  pneumatic  hoist  having  a  wind- 
ing drum  driven  by  cylinders. 

The  machines  shown  in  the  following  figures  repre- 
sent a  few  of  the  special  foundry  machines.  The  sand 


Fig.  95. 

sifter  shown  in  Fig.  98  is  driven  by  belt  but  may  be 
fitted  with  a  hand  wheel  for  hand  power. 

Fig.  99  represents   a  rotary  sand  sifter   which   is 

belt-driven. 


Fig.  96. 


190  FOUNDRY  PRACTICE 


Fig.  97. 


1'OUNDRY  PRACTICE 


191 


Figs.  100  and  101  are  sand  mixers  having  paddles 
which  rotate  to  mix  the  sand  thoroughly. 


Fig.  98. 


Fig.  102  is  a  centrifugal  mixer.    The  sand  entering 


Fig.  99- 


192 


FOUNDRY  PRACTICE 


from  the  hopper  falls  upon  a  rotating  disk  which  throws 
the  sand  by  centrifugal  force,  thus  mixing  it. 


Fig.  100. 

These  mixers  are  of  especial  advantage  in  mixing 
facings  or  sands  of  different  kinds  where  a  thorough 
mixing  is  necessary. 

Fig.  103  represents  a  sand  crusher.  The  pan  hold- 
ing the  sand  rotates  under  the  rolls  and  the  sand  is  loos- 


Fig.  101. 


FOUNDRY   PRACTICE 


193 


ened  by  fixed  paddles  between  the  rolls.  These  paddles 
may  serve  as  a  mixer  also  and  are  used  in  mixing  the 
sand  and  clay  for  the  facing  of  molds  for  steel  castings. 


Fig.  102. 


Fig.  103. 


CHAPTER  X 

The  manufacture  of  steel  castings  is  greatly  increas- 
ing in  extent  and  variety  of  castings  made.  The  in- 
dustry is  young,  so  that  it  has  not  been  developed  to  its 
fullest  extent.  A  few  brief  points  will  here  be  given 
which  may  give  the  iron  worker  an  idea  of  methods 
necessary  in  making  steel  castings. 

The  mold  is  formed  in  sand  which  may  be  green  or 
dried  to  suit  the  type  of  work.  The  same  mixtures  are 
used  in  both  cases.  The  sand  is  a  very  open  mixture 
with  sufficient  clay  to  form  a  binder.  The  following 
mixture  may  be  taken  as  a  guide : 

Mix  3  parts  coarse  sharp  sand  98%   SiO2,  2  parts  fiae 
sharp  sand  95%  SiO2,  i  part  red  clay. 

This  mixture  should  be  thoroughly  blended  and 
crushed  in  a  sand  crusher.  This  is  used  as  a  facing, 
while  the  heap  sand  from  former  molds  is  used  as  a 
backing  sand. 

The  mold  is  rammed  very  hard  so  that  in  the  green 
form  it  is  nearly  as  hard  as  a  dry  sand  mold  for  iron. 
The  sand  is  tempered  to  hold  together  but  is  kept  as  dr\ 
as  possible.  When  the  mold  is  dried  it  becomes  very 
hard  and  has  great  strength  to  resist  pressure. 

Steel  will  cut  the  sand  much  more  readily  than  iron. 
All  edges  and  projections  must  be  well  nailed  so  that 
the  heads  hold  the  surface  of  the  sand.  All  large  plane 
surfaces  must  be  nailed  quite  closely  to  prevent  cutting 
in  the  drag  and  drawing  down  the  cope. 


FOUNDRY  PRACTICE  195 

Owing  to  the  hard  ramming,  the  pattern  is  hard  to 
remove,  hence  the  exact  form  of  casting  is  not  obtained 
so  easily  as  in  iron.  Particular  forms,  as  gear  teeth, 
are  more  difficult  to  obtain  in  steel  than  in  iron. 

The  metal  must  be  of  a  higher  temperature  than 
iron  in  order  to  maintain  fluidity.  Hence  it  sets  more 
quickly  and  usually  is  duller  when  poured  than  iron.  The 
gates  must  be  made  correspondingly  large  to  allow  the 
mold  to  fill  quickly,  or  the  light  or  sharp  parts  will  not 
run.  The  shrinkage  is  about  double  that  of  iron,  and 
takes  place  very  soon  after  pouring.  A  riser  must  be 
provided  of  adequate  size  to  feed  the  shrinkage.  The 
feeding  rod  can  not  be  used  as  effectively  as  in  iron, 
hence  the  riser  must  act  more  as  a  sinking  head. 

Castings  of  such  form  that  they  crush  the  sand  of 
the  mold  when  shrinkage  takes  place  are  sometimes 
found  to  be  broken  or  drawn  weak  in  places  when  they 
come  from  the  mold.  This  is  due  to  the  casting  being 
unable  to  crush  the  sand  to  permit  the  shrinkage.  This 
may  be  prevented  by  cutting  a  gutter  on  the  parting  of 
the  flask  about  2  in.  from  the  casting  and  connecting  this 
gutter  by  an  opening  through  the  cope.  As  soon  as  the 
casting  has  set  the  gutter  is  filled  with  water,  which 
softens  the  sand,  making  it  easier  to  crush.  In  some 
cases,  castings  of  quite  intricate  and  large  size  have  been 
made  more  successfully  in  green  sand  than  in  dry  owing 
to  the  mold's  resistance  to  crushing. 

The  chief  methods  of  melting  steel  for  steel  casting 
are  by  the  cupola  or  by  a  converter.  Steel  is  success- 
fully melted  in  the  cupola  the  same  as  iron.  The  higher 
temperature  required  offers  many  difficulties  which  are 
a  drawback  to  the  process.  It  is  hard  to  obtain  good 
fluidity  in  the  cupola.  The  converter  gives  steel  of  the 


196  FOUNDRY  PRACTICE 

composition  desired,  and  the  fluidity  is  much  more  per- 
fect. 

Formerly  steel  was  melted  in  a  crucible,  similarly  to 
brass,  but  this  is  an  expensive  method  which  is  not 
used  except  in  isolated  cases.  The  bottom  blow,  side 
blow,  and  open  hearth  converter  are  the  most  econom- 
ical producers  of  steel  for  castings.  Where  the  furnace 
can  be  kept  in  operation  continuously,  the  open  hearth 
furnace  presents  many  advantages.  For  intermittent 
heats,  the  bottom  or  side  blow  converter  gives  the  best 
results.  The  side  blow  converter  proves  preferable,  as 
the  iron  used 'may  be  lower  in  silicon  and  yet  obtain  a 
good  steel;  and^besides  the  steel  becomes  superheated, 
which  better  permits  handling  and  pouring. 

In  the  open  hearth  furnace,  the  metal  is  melted  and 
reduced  in  its  bath.  Any  kind  of  iron  or  steel  scrap  may 
be  charged.  The  product  is  tested  by  a  sample  and  is 
poured  when  the  steel  is  of  the  nature  desired.  The 
process  is  slow,  taking  from  eight  to  twelve  hours  to 
reduce  a  charge. 

In  the  blow  converter,  the  reduction  takes  place  in  a 
very  few  minutes.  The  iron  for  the  charge  is  melted  in 
a  cupola  and  put  into  the  converter  in  the  molten  state. 
The  progress  of  the  conversion  is  told  by  the  gases  which 
pass  off  at  the  top.  When  the  desired  amount  of  impur- 
ities have  been  removed,  a  charge  of  spiegeleisen  is  mixed 
with  that  in  the  converter,  giving  a  product  of  the  de- 
sired percentage  of  carbon.  The  steel  may  be  varied  by 
varying  the  percentage  of  spiegeleisen  charged.  The  blast 
is  turned  off  before  charging  the  spiegeleisen.  The  two 
charges  in  the  converter  are  allowed  to  mix,  then  it  is 
poured  out  ready  for  the  molds. 

The  iron  used  for  the  converter  should  have  about 


FOUNDRY  PRACTICE  197 

2  per  cent,  of  silicon,  phosphorus  below  0.06  per  cent., 
manganese  as  low  as  possible,  and  sulphur  very  low. 

A  mixture  that  may  be  substituted  for  the  ore  spie- 
geleisen   is   given  below : 

95  Ibs.  of  ferrous  silicate,  45  Ibs.  of  manganese,  65  Ibs. 
of  pig  iron  which  is  low  in  phosphorus  and  high  in 
silicon. 


CHAPTER  XI 

Brass  molding  is  so  similar  to  iron  molding  that  a 
description  is  unnecessary.  One  is  different  from  the 
other  only  in  the  particular  that  gating  and  venting  must 
be  given  more  consideration.  The  sand  used  for  brass 
molding  is  much  finer,  and  when  rammed  in  the  flask, 
it  must  be  well  vented,  or  unsound  castings  will  result. 
The  metal  used  in  brass  casting  is  of  a  nature  that  will 
not  permit  an  unnecessarily  high  temperature,  as  the 
castings  will  not  then  be  sound.  Long  runners  cool  the 
metal  so  as  to  prevent  its  filling  the  mold  properly.  Short 
runners  and  a  liberal  amount  of  gating  are  desirable. 
The  sand  most  used  for  brass  molding  is  the  Albany. 
This  sand  is  fine  and  gives  entire  satisfaction  for  ordi- 
nary brass  work ;  but  for  heavy  work  in  brass,  and  when 
the  casting  is  to  be  finished,  the  mold  is  made  in  a 
coarse  and  more  open  sand.  Sometimes  it  is  advisable  to 
make  the  mold  in  dry  sand  for  heavy  work.  In  pouring 
the  metal  into  the  mold,  it  should  be  run  as  rapidly  as 
possible  until  the  mold  is  filled.  On  heavy  castings  it  is 
very  necessary  to  provide  the  mold  with  a  riser  or 
shrinking  head,  as  the  shrinkage  in  brass  or  bronze  is 
greater  than  in  cast  iron.  After  the  metal  has  been  cast 
it  may  be  cooled  in  water  as  soon  as  it  has  solidified. 

By  slowly  cooling  the  brass  becomes  hard,  and  by 
sudden  cooling  the  brass  may  be  softened.  The  immers- 
ing in  water  gives  the  sudden  cooling,  and  besides  re- 
moves the  sand  from  the  casting. 


FOUNDRY  PRACTICE 


199 


In  preparing  the  mold  for  brass,  the  ordinary  facings 
used  in  iron  molds  are  unnecessary.  Plumbago  is  sel- 
dom used  except  in  heavy  castings ;  for  light  and  medium 
work,  flour,  pulverized  soapstone,  charcoal,  and  some- 
times plaster  of  Paris  or  bone  dust  are  used.  In  very 
light  castings,  nothing  is  necessary  except  very  fine 
molding  sand. 

Very  good  results  are  obtained  in  small  work  by 
using  a  very  fine  sand  and  spraying  the  mold  with  gas- 
oline, lighting  it,  and  allowing  it  to  burn  off.  This 


Fig.  104. 

skin-dries  the  mold  and  prevents  the  metal  from  wash- 
ing or  cutting  the  mold  in  pouring. 

The  snap  flask  is  sometimes  used  in.  brass  molding, 
but  for  small  and  for  light,  thin  castings  the  flask  shown 
in  Fig.  104  is  more  convenient.  This  flask  is  provided 
with  openings  at  one  end  which  are  used  for  pouring- 
holes.  When  the  mold  is  ready  to  cast  it  is  set  on  end 
with  the  openings  up.  This  gives  more  force  to  the  meta! 


200 


FOUNDRY  PRACTICE 


and  greater  pressure  in  the  mold.     This  also  avoids  the 
chilling  of  the  metal  before  it  reaches  the  mold. 

Brass  founding  differs  somewhat  from  iron  found- 
ing, for  the  reason  that  the  metal  is  of  a  different  charac- 
ter and  must  be  treated  differently.  Brass,  or  copper 
alloys,  can  not  be  melted  in  a  cupola  furnace  and  sound 
castings  be  obtained.  The  metal  coming  in  contact  with 
the  fuel  is  impregnated  with  impurities,  which  causes 


Fig.  105. 


FOUNDRY  PRACTICE 


20 1 


unsound  castings.  A  simple  form  of  furnace  for  melting 
brass  is  shown  in  Fig.  105.  The  more  improved  fur- 
nace is  shown  in  Fig.  106.  To  prevent  the  metal  from 
coming  in  contact  with  the  fuel,  a  crucible  is  used.  The 
crucible  containing  the  metal  is  placed  in  the  furnace,  as 
shown  in  Fig.  105.  The  crucible  is  handled  by  means  of 


Fig.  106. 

tongs,  as  shown  in  Fig.  107.  The  furnace  is  connected 
with  a  chimney  or  smoke  stack  of  sufficient  height  to 
furnish  draft.  Mechanical  draft  is  however  applied  in 
some  cases.  The  furnace  shown  in  Fig.  106  is  sup- 


202  FOUNDRY  PRACTICE 

plied  with  both  natural  and  mechanical  draft.  This  ar- 
rangement is  best.  While  the  natural  draft  is  cheaper, 
there  are  days  when  the  draft  is  inadequate  and  the 
melting  slow.  At  such  times,  it  is  desirable  to  use 
mechanical  draft  for  faster  melting.  Foundry  coke  or 
anthracite  coal  is  used  in  this  type  of  furnace. 

In  Fig.  105,  the  portion  marked  A  is  the  fire  cham- 
ber, B  the  ash  pit  through  which  the  air  is  admitted  to 
the  grate  C,  and  D  the  flue  connecting  with  the  chimney 
or  stack.  The  ash  pit  in  front  and  underneath  the  fire 
chamber  is  covered  by  a  grating  which  may  be  lifted 
off  when  it  is  necessary  to  remove  the  ashes  from  the 
pit.  The  fire  chamber  cover  E  is  provided  with  an  up- 


Fig.  107. 

right  handle  to  enable  the  operator  to  remove  the  cover 
when  the  furnace  is  hot.  The  fire  chamber  is  con- 
structed of  fire  brick  and  is  cylindrical  in  form.  The 
bottom  plate  F  which  supports  the  fire  chamber  is  square, 
having  a  round  opening  at  its  centre  the  same  diameter 
as  the  chamber.  This  plate  is  made  of  cast  iron  and  is 
supported  in  the  brick  wall  at  the  back  and  sides  of 
the  ash  pit.  The  grate  underneath  the  plate  is  composed 
of  single  iron  bars  placed  the  proper  distance  apart  and 
supported  by  cross  bars  at  front  and  back  extending  into 
the  sidewalls  of  the  pit.  The  single  bar  grate  is  pre- 
ferred by  many,  on  account  of  the  convenience  in  clean- 
ing the  fire  without  rebuilding.  After  one  heat  has 


FOUNDRY  PRACTICE 


203 


been  taken,  it  is  desirable  to  clear  the  furnace  of  cinders 
and  ashes  which  form  on  the  grate.  This  is  difficult  to 
do  with  the  drop  grate  as  shown  in  Fig.  106.  The  single 
bars  may  be  jarred  sidewise  with  a  long  bar  reaching 


Fig.  108. 

through  the  grating  on  the  ash  pit,  thus   saving  much 
time. 

To  prepare  for  melting  in  this  type  of  furnace,  remove 
the  grate  bars,  clear  the  furnace  of  ashes  and  clinkers, 
adjust  the  bars  in  their  place,  put  in  a  sufficient  amount 


204 


FOUNDRY  PRACTICE 


of  wood  to  start  the  coal  or  coke  to  burning,  and  add 
enough  fuel  to  form  a  bed  10  in.  or  12  in.  in  depth. 
After  the  fuel  is  well  ignited,  place  the  crucible  with 


Fig.  109. 

metal  on  the  bed  of  coals  and  add  fuel  around  the  crucible 
to  near  its  top.  As  the  fuel  burns  away  at  the  bottom 
of  the  furnace,  the  crucible  must  be  raised  slightly  and 
more  fuel  added  around  its  outside.  While  this  is  being 
done,  care  must  be  taken  to  prevent  fuel  falling  inside 


FOUNDRY  PRACTICE  205 

the  crucible,  as  this  is  a  source  of  damage  to  the  metal. 
More  metal  may  be  added  when  that  in  the  crucible  melts 
?.nd  settles.  When  the  metal  has  become  fluid  enough  to 
run  well,  it  should  not  be  allowed  to  remain  in  the  fur- 
nace, but  should  be  removed  with  the  crucible  tongs  and 
poured.  If  allowed  to  stand  or  if  overheated,  the  metal 
will  be  damaged. 

There  are  still  more  modern  and  improved  brass  melt- 
ing furnaces  than  those  mentioned.  Among  others  are 
the  Schwartz  metal  melting  and  refining  furnace  and  the 


Fig.  no. 

Charlier  rolling  furnace.  These  furnaces  are  heated  by 
fuel  oil  or  gas.  They  are  very  efficient  and  economical  on 
account  of  rapid  melting.  The  Schwartz  furnace  is 
shown  in  Fig.  108.  This  furnace  is  lined  with  fire  brick 
and  is  supported  by  trunnions  having  a  bearing  on  pedes- 
tals. Air  and  oil  are  supplied  at  an  opening  through  the 
trunnion  at  one  end.  The  flow  of  oil  is  obtained  by  p. 
standpipe,  by  pumping,  or  by  air  pressure  in  the  tank. 
The  air  is  supplied  from  a  blower  or  from  a  storage  tank 


206 


FOUNDRY  PRACTICE 


FOUNDRY  PRACTICE  207 

of  compressed  air,  and  is  regulated  by  a  valve.     Fig.  10^ 
is  a  general  view  of  the  furnace  and  its  arrangement. 

The  Charlier  rolling  furnace  is  shown  in  Fig.  no. 
This  furnace  consists  of  a  metallic  casing  lined  with  fire 
brick  and  having  an  opening  in  the  centre  of  rotation  at 
one  end,  through  which  the  fuel  and  air  are  admitted  to 
the  melting  chamber.  The  arrangement  of  this  furnace 
is  similar  to  the  one  previously  shown.  Fig.  in  shows 
a  general  plan  of  a  plant  equipped  with  a  Charlier  fur- 
nace. 


CHAPTER  XII 

CAST    IRON    ALLOYS. 

To  toughen  cast  iron:  10  to  15  per  cent,  of  wrought 
iron  scrap  (stirred  in)  ;  V^  to  i  per  cent,  of  copper 
(stirred  in). 

To  toughen  cast  iron  or  to  form  semi-steel :  Add  from 
5  to  30  per  cent,  oi  steel  scrap  to  the  charge  of  iron  in 
the  cupola. 

To  harden  scrap  iron:  Mix  ^  pint  vitriol,  i  peck  com- 
mon salt,  */2  Ib.  saltpetre,  2  Ibs.  alum,  %  Ib.  prussic 
potash,  l/^  Ib.  cyanide  potash.  Dissolve  the  mixture  in 
10  gals,  of  soft  water.  Heat  the  iron  to  a  cherry-red 
and  dip  into  the  solution.  For  a  harder  and  deeper 
skin  on  the  iron,  repeat  the  heating  and  dipping  two 
or  more  times. 

To  soften  or  to  anneal  cast  iron:  Heat  to  a  cherry-red, 
then  pack  in  a  coating  of  bone-black  and  cover  with 
ashes  to  allow  cooling  very  slowly. 


GLOSSARY 

Air-dried — The  surface  drying  of  cores  left  in  open 
air  too  long  before  placing  in  oven.  Molds  left  open 
also  dry  out  on  surface,  causing  crumbling  or  washing 
when  metal  is  poured. 

Air  hoist — a  piston  and  cylinder  suspended  from  an 
overhead  track  or  traveling  crane  and  operated  by  com- 
pressed air.  For  hoisting  ladles,  flasks,  or  weights  in 
the  foundry. 

Alloy — any  compound  of  two  or  more  metals,  as 
copper  and  zinc  to  form  brass. 

Anchor — a  contrivance  used  to  hold  parts  of  the 
mold  down  or  together.  See  Pulley  anchor. 

Arm — the  portion  of  a  pulley  which  connects  the 
hub  and  the  rim. 

Ash  pit — the  space  underneath  a  fire  box,  in  a  core 
oven  or  brass  furnace,  to  receive  the  ashes  which  fall 
from  the  grate. 

Bars — the  framework  inside  the  cope  of  a  molding 
flask,  to  retain  the  molding  sand  in  position  while  lifting 
or  handling  the  flask,  and  also  to  resist  the  pressure  of 
metal  when  casting. 

Batten — a  piece  attached  to  a  thin,  flat  pattern  for 
the  purpose  of  strengthening  and  keeping  it  straight; 
not  a  part  of  the  pattern  nor  to  be  a  part  of  the  casting. 
It  should  be  marked  "stop-off,"  and  the  recess  formed 
by  this  piece  in  the  mold  should  be  filled  up  or  stopped 
off  after  the  pattern  has  been  removed  from  the  sand. 


2iO  GLOSSARY 

Bed  charge — the  first  or  lower  charge  of  coke  in  a 
cupola,  reaching  from  the  bed  or  bottom  to  a  point  above 
the  tuyeres. 

Bedding  in — the  process  of  molding  a  pattern  by 
embedding  it  in  the  sand  in  the  exact  position  in  which 
it  is  to  be  cast. 

Bellows — an  instrument  for  forcing  air  through  a 
tube.  Used  in  foundries  for  the  purpose  of  blowing  away 
loose  sand  from  the  molds. 

Binders — the  various  articles  used  in  loam,  core 
sand,  and  facings  for  the  purpose  of  holding  the  sand 
together  when  dry,  such  as  glue  water,  molasses,  lin- 
seed oil,  flour,  etc. 

Blacking — a  thin  facing  of  carbon,  consisting  of  pul- 
verized charcoal  or  plumbago,  by  which  the  fusible  in- 
gredients of  the  sand  are  protected  from  the  intense  heat 
of  the  metal  when  casting.  Blacking  is  sometimes  ap- 
plied as  a  powder  to  green  sand  molds ;  but  for  dry  sand, 
loam,  or  skin-dried  molds  and  cores  wet  blacking  or  black 
wash  is  used.  Wet  blacking  consists  of  common  blacking 
mixed  with  .water  thickened  with  clay  to  the  consistency 
of  thin  paint.  Wet  blacking  somewhat  hardens  the  sur- 
face of  a  mold  when  dry. 

Black  lead. — See  Graphite. 

Blast — the  current  of  atmospheric  air  delivered 
from  the  blower  or  fan  under  pressure  through  the 
blast  pipe  and  tuyeres  into  the  cupola. 

Blast  gauge — the  blast  gauge  is  a  device  to  de- 
termine the  amount  of  pressure  in  the  wind  belt  or 
jacket  of  a  cupola  while  in  operation.  This  instru- 
ment is  a  form  of  manometer. 

Blast  pipe — the  pipe  through  which  the  air  passes 
from  the  fan  or  blower  to  the  cupola. 


GLOSSARY 


211 


Blower — a  box  with  revolving  wings  or  vanes  in- 
side, so  constructed  and  arranged  as  to  force  a  pres- 
sure of  air  through  the  blast  pipe  into  the  cupola. 

Blow-holes — holes  occurring  in  castings,  due  to  air 
and  gas  in  the  metal  and  in  the  mold  when  casting. 
Blow-holes  are  the  result  of  insufficient  venting  and  of 
moisture. 

Bott  stick — a  stick  of  wood  or  bar  of  iron  with  one 
flat  end  on  which  to  place  a  ball  of  clay  in  stopping  the 
flow  of  iron  from  the  cupola. 

Bottom  board — the  board  on  which  the  flask  rests 
when  in  position  to  cast.  It  may  be  of  iron  or  wood. 

Breast — the  clay  front  built  in  the  opening  over  the 
spout  of  the  cupola  and  through  which  the  tapping  port 
is  made. 

Bricking  up — building  up  the  skeleton  of  a  loam 
mold  by  means  of  bricks  cemented  together  with  loam. 

Bull  ladle — a  vessel  for  handling  molten  metal.  It 
is  placed  in  a  shank  and  is  carried  by  two  or  more  men. 

Burning  on,  or  casting  on — the  process  of  mending 
cracked  or  broken  castings  or  of  adding  on  metal,  where 
the  casting  is  unsound  or  incomplete,  by  means  of  flowing 
molten  metal  over  the  part  to  be  treated  until  fusion  takes 
place. 

Burnt  sand — sand  which  has  had  contact  with 
molten  metal.  The  sand  which  forms  the  face  of  a 
mold  invariably  becomes  burnt. 

Butting,  or  butt  ramming — the  process  of  butting 
or  ramming  the  sand  with  the  flat  end  of  the  rammer. 

Camber — the  curving  of  certain  types  of  casting  in 
cooling,  due  to  want  of  symmetry  in  their  sectional 
forms,  by  reason  of  which  one  portion  cools  off  more 


212  GLOSSARY 

rapidly  than  the  other,  causing  distortion  of  figure  in  the 
longitudinal  direction. 

Carrier — a  casting  which  is  attached  to  the  arm  of  a 
gear  molding  machine  and  •  to  which  the  tooth  block  is 
attached. 

Casting — a  piece  of  metal  work  obtained  by  pour- 
ing molten  metal  into  a  mold. 

Casting  on — the  same  as  burning  on. 

Changing  hook — an  S  crane  hook  which  is  double 
at  one  end  and  which  is  useful  in  transferring  from  one 
crane  to  another. 

Chaplet. — Chaplets  are  iron  supports  to  retain  a 
core  in  its  proper  position  where  core  prints  can  not  be 
used. 

Chaplet  block — a  block  of  wood  rammed  in  the  sand 
to  receive  the  spike  of  a  chaplet  nail.  The  block  affords 
the  requisite  steadiness  to  the  chaplet  when  in  position. 

Chaplet  nails — a  chaplet  with  one  end  flat  and  the 
other  a  sharp  point  to  be  driven  into  the  bottom  board 
or  into  a  block  of  wood  rammed  .up  in  the  sand  which 
forms  the  mold. 

Charcoal — coal  made  by  charring  wood.  It  is  used 
in  drying  molds.  Oak  charcoal  pulverized  is  used  for  the 
purpose  of  blackening  molds. 

Cheek — an  intermediate  part  of  a  mold  where  more 
than  two  parts  are  necessary. 

Chill — a  metal  form  placed  in  a  mold  or  forming  a 
portion  of  the  mold  against  which  the  iron  is  poured  to 
produce  a  chilled  casting. 

Chilled  casting — a  casting  whose  surface  is  hard- 
ened by  pouring  molten  iron  against  a  chill. 

Cinder  bed — a  bed  or  layer  of  cinders  or  coke  placed 
below  a  pit  mold  for  the  purpose  of  carrying  off  the  gases 


GLOSSARY  213 

that  pass  downward.  The  cinder  bed  is  connected  to  the 
surface  by  a  vent  pipe. 

Clamps — are  wrought  or  cast  iron  bars  whose  ends 
form  a  right  angle;  they  are  useful  in  binding  together 
the  top  and  bottom  of  a  flask  while  pouring  the  metal. 

Clamping — placing  the  clamps  in  their  proper  posi- 
tion on  the  flask  when  the  mold  is  completed. 

Clay  wash — a  mixture  of  clay  and  water. 

Coke  bed. — See  Cinder  bed. 

Cold  shots — small  globular  particles  of  metal  which 
are  formed  by  the  first  splashing  of  metal  in  a  mold  and 
which  harden  quickly  and  do  not  amalgamate  with  the 
other  metal  in  the  mold. 

Cold-shuts — are  produced  by  pouring  the  metal  too 
cold  or  too  slowly  into  the  mold  and  are  due  to  imperfect 
amalgamation  of  the  metal  in  the  mold.  They  may  also 
be  caused  by  gases  in  the  mold,  arising  from  the  use  of 
facing  sand  containing  too  great  a  percentage  of  sea  coal. 

Contraction. — See  Shrinkage. 

Cope — the  top  part  of  a  flask  or  mold. 

Core — a  body  of  sand  in  the  mold  for  forming  inte- 
rior openings  or  holes  in  the  casting. 

Core  barrel — a  hollow  bar  or  pipe  on  which  a  cylin- 
drical core  is  formed.  The  barrel  gives  the  core  strength 
and  also  openings  through  the  sides,  affording  vent  for 
the  gases  generated  in  casting  the  metal  around  the  core. 

Core  boafd — a  board  whose  edge  is  profiled  to  a  sec- 
tional form  of  a  desired  core. 

Core  box — a  box  in  which  a  core  is  to  be  formed  or 
molded.  Its  interior  shape  to  be  the  same  as  the  outside 
form  of  core  desired. 

Core  carriage — a  carriage  upon  which  the  cores  are 


2i4  GLOSSARY 

placed  after  being  molded  and  on  which  they  are  con- 
veyed into  the  drying  oven. 

Core  irons — rods  or  bars  of  iron  rammed  up  in  a 
core  to  give  it  strength. 

Core  lathe — a  frame  having  V's  or  bearings  in 
which  to  place  a  core  barrel  provided  with  a  crank,  on 
which  barrel  a  core  is  to  be  formed  and  trued  up  by 
revolving  the  core  against  a  sweep  which  forms  the 
desired  shape  of  the  core. 

Core  mixture — a  core  sand  dampened  and  mixed 
with  a  binder  in  such  proportions  that  when  dry  it  will 
become  hard. 

Core  oven — an  oven  in  which  to  bake  or  dry  cores 
after  molding  them. 

Core  plate — a  plate  on  which  cores  are  formed  or 
placed  while  drying. 

Core  print — an  attachment  or  projection  on  a  pat- 
tern which  forms  a  seat  or  pocket  in  the  sand  in  which 
the  core  is  to  be  placed  hi  the  mold  after  the  pattern 
has  been  removed. 

Core  rope — ropes  or  strings  used  for  forming  vents 
in  crooked  cores,  from  which  rods  or  wires  could  not  be 
withdrawn  without  damage  to  the  core. 

Core  sand — any  sharp  sea  sand  or  nearly  pure  silica. 

Core  trestles — upright  standards  or  trestles  whose 
tops  are  provided  with  V-shaped  recesses  or  bearings  in 
which  to  place  the  ends  of  a  core  bar  or  barrel  while  re- 
volving to  sweep  up  a  core. 

Core  wash. — See  Blacking. 

Crane — a  device  for  lifting  and  moving"  heavy 
weights  in  a  foundry,  such  as  flasks,  weights,  and 
ladles  of  molten  metal. 

Crane  ladle. — See  Ladle. 


GLOSSARY  215 

Crushing — compressing  the  sand  in  the  mold  by 
too  great  strain  on  the  clamps  after  the  pattern  has 
been  withdrawn,  causing  the  mold  to  crumble  and  sand 
to  fall  into  the  mold. 

Crystalline  fracture — where  the  face  of  the  break 
shows  a  coarse  formation  of  crystals. 

Cupola — a  cylindrical  furnace  for  melting  iron.  A 
cupola  is  lined  with  fire  brick  and  provided  with  ports 
or  tuyeres  near  its  base  through  which  a  pressure  of 
air  is  forced. 

Cutting  over — the  process  of  shovelling  over  the 
sand  to  obtain  an  even  mixture  and  temper. 

Daubing — lining  or  plastering  up  the  interior  of  a 
cupola  or  ladle  with  clay  or  molding  sand.  The  operation 
is  performed  with  the  hands. 

Dowell — a  pin  of  wood  or  metal  used  to  hold  the 
parts  of  a  divided  pattern  in  their  respective  positions 
while  they  are  being  rammed  in  the  sand. 

Draft — the  allowance  or  slight  taper  made  on  a  pat- 
tern to  aid  in  its  removal  from  the  sand  after  being 
rammed  up.  The  portion  of  the  pattern  at  the  parting 
line  of  the  mold  must  be  larger  than  that  extending  into 
the  cope  or  drag. 

Drag — the  lower  part  of  a  mold  when  in  position 
to  be  cast. 

Draw. — The  casting  draws  when  the  shrinkage 
causes  depressions  of  the  surface  or  openings  in  the  in- 
terior. See  Drawing. 

Drawback — a  section  of  a  mold  rammed  up  sepa- 
rate from  the  drag  and  cope  and  parted  by  a  plate  or 
piece  of  cloth,  and  which  may  be  drawn  back  for  the 
convenience  of  the  molder  in  removing  the  pattern  or 
in  patching  the  mold. 


216  GLOSSARY 

Drawback  plate — the  iron  plate  on  which  a  draw- 
back is  rammed  up. 

Drawing — removing  the  pattern  from  the  sand 
after  the  mold  has  been  formed,  also  increasing  the 
depth  of  a  mold  without  altering  the  dimensions  of  the 
pattern  by  drawing  the  pattern  a  part  of  the  length  up- 
ward and  ramming  the  sand  around  its  upper  portion. 

Draw  plate — a  plate  attached  to  a  pattern  for  the 
purpose  of  receiving  the  rapping  iron  and  lifting  screw. 

Draw  spike — a  tool  pointed  at  one  end  to  be  driven 
into  the  pattern  for  the  purpose  of  lifting  it  from  the  sand. 

Drop-out — the  whole  or  part  of  the  sand  falling  out 
of  the  cope  of  a  mold  while  turning  over  or  closing  a 
flask. 

Drying — the  process  of  evaporating'moisture  from 
a  mold  by  means  of  hot  air  injected,  or  of  a  charcoal 
fire  basket,  or  by  baking  in  an  oven. 

Dry  sand — mixtures  of  sand  which  after  being 
dried  in  an  oven  or  otherwise  becomes  hard  and  better 
resists  the  strain  from  molten  metal. 

Dull  iron — iron  which  has  not  been  heated  to  a 
proper  temperature,  or  which  has  been  allowed  to  re- 
main in  the  ladle  too  long  before  pouring.  Dull  iron 
causes  seams,  cold-shuts,  and  unsound  castings. 

Facing — any  material  used  to  mix  with  the  sand  for 
the  purpose  of  preventing  the  fusion  of  the  sand  and  the 
metal.  Pulverized  sea  coal  is  commonly  used. 

Facing  sand — the  mixture  of  sand  which  forms  the 
face  of  the  mold. 

Fan — an  apparatus  provided  with  revolving  wings 
enclosed  within  a  case  for  the  purpose  of  forcing  air 
into  the  blast  pipe  of  a  cupola. 

Feeder  head — a  body  of  molten  metal  contained  in 


GLOSSARY  217 

a  riser  or  opening  above  a  mold  for  the  purpose  of  sup- 
plying metal  to  the  mold  when  shrinkage  takes  place. 

Feeding — forcing  the  metal  into  the  mold  from  the 
feeding  head  during  the  time  it  is  liquid  by  means  of  an 
iron  rod  kept  in  motion  vertically  in  the  feeding  head. 
It  is  sometimes  termed  pumping  a  mold. 

Feeding  rod — a  wrought  iron  bar  used  for  the  pur- 
pose of  feeding  a  mold. 

Fin — a  thin  projection  on  the  casting  at  the  parting 
line  of  the  mold,  caused  by  an  imperfect  joint. 

Fire  clay — a  kind  of  clay  which  will  sustain  intense 
heat  and  which  is  used  in  furnaces,  cupolas,  and  ladle 
linings. 

Flask — a  box  or  frame  in  which  a  mold  is  formed. 
A  flask  must  consist  of  two  or  more  parts  and  may  be 
made  of  either  wood  or  metal. 

Flow-off  gate — a  vertical  passage  through  which 
the  metal  flows  after  the  mold  has  been  filled.  Its  top 
is  lower  than  the  level  of  the  pouring  gate. 

Flux — any  material  used  in  a  melting  furnace  or  cu- 
pola to  cause  the  slag  to  become  more  liquid  and  more 
easily  drawn  off  before  tapping  out  the  iron.  Limestone 
is  commonly  used. 

Follow-board — a  board  which  conforms  to  the  form 
of  the  pattern  and  defines  the  parting  surface  of  the 
drag. 

Foundation  plate — a  plate  of  cast  iron  placed  in  the 
bottom  of  a  mold  to  receive  the  spindle  to  maintain  a 
sweep. 

Founding — the  casting  of  metal  in  molds.. 

Fusing — the  iron  and  sand  are  said  to  fuse  when  a 
hard  coating  of  sand  adheres  to  the  metal  after  casting, 
due  to  the  heat  of  the  molten  metal. 


218  GLOSSARY 

Gaggers — are  made  of  iron  in  the  shape  of  the  letter 
L  and  are  used  for  the  purpose  of  anchoring  the  sand  to 
be  lifted  in  the  cope  of  a  mold. 

Gangway — the  passages  between  the  molding 
floors  and  leading  from  the  cupola.  The  gangway  is 
usually  laid  with  iron  plates  over  which  trucks  or  ladle 
carriages  are  run. 

Gate — the  terminus  of  the  runner  where  the  metal 
enters  the  mold.  The  opening  through  the  cope  left  by 
the  gate  stick  is  commonly  called  the  gate  or  sprue. 

Gate  cutter — a  piece  of  thin  sheet  metal  bent  to  the 
shape  of  the  letter  U ;  it  is  used  to  cut  the  runners  which 
conduct  the  metal  to  the  mold. 

Gate  stick — a  wooden  pin  or  stick  used  by  the 
molder  to  form  the  opening  leading  from  the  pouring 
basin  to  the  runner.  It  is  placed  in  position  before  the 
sand  is  rammed  in  the  cope. 

Grab  hook — hooks  connected  by  short  chains  or 
rods  for  the  purpose  of  attaching  loads  to  the  crane 
hook. 

Graphite — carbon  in  one  of  its  conditions,  distin- 
guished by  its  usually  crystallizing  in  foliated,  six- 
sided  prisms,  though  often  massive,  by  its  softness,  by 
its  metallic  luster,  and  by  leaving  a  dark  lead-colored 
trace  on  paper.  It  is  often  called  plumbago  or  black 
lead. 

Green  sand — common  molding  sand  suitably  tem- 
pered to  form  molds  for  metal  without  subsequent 
drying. 

Gutters — shallow  channels  cut  at  the  parting  of  a 
mold  for  the  purpose  of  receiving-  the  vents  which  are 
led  oft"  at  the  parting  and  of  conducting  them  to  a  relief 
vent. 


GLOSSARY  219 

Hand  ladle. — See  Ladle. 

Hard  ramming — ramming  the  sand  in  a  mold  until 
hard.  Some  molds  should  be  rammed  hard  to  resist  the 
pressure  of  the  metal. 

Hatching  up — cutting  or  roughening  the  surface  of 
a  mold  for  the  purpose  of  better  holding  new  sand 
which  may  be  added  in  patching. 

Hay  rope — hay  twisted  or  spun  to  the  form  of  a 
rope,  used  to  wind  around  a  core  barrel  or  hollow  bar 
in  striking  up  round  cores  or  loam.  The  hay  holds  the 
sand  or  loam  to  the  bar  and  also  affords  escape  for  the 
gases. 

Hot  metal — metal  which  is  in  its  most  liquid  state. 
Light  and  thin  castings  should  be  poured  with  hot  metal. 

Ladle — an  iron  vessel  lined  with  fire  clay  and  used 
in  handling  molten  metal  from  the  cupola  to  the  mold. 
Hand  ladles  are  carried  by  one  man  and  bull  ladles  by 
two  or  more.  Crane  ladles  are  handled  by  the  crane. 

Leveling — making  a  bed  of  sand  level  by  the  use  of 
parallel  strips,  a  straight  edge  and  a  level. 

Leveling  strips — parallel  strips  used  in  leveling 
sand  beds. 

Lifter — a  tool  used  for  removing  loose  sand  from 
the  bottom  of  deep  molds. 

Lifting  screw — an  iron  rod  with  a  screw  or  thread 
cut  at  one  end  and  an  eye  or  loop  at  the  other.  The  screw 
may  be  used  in  the  wood  pattern  and  the  thread  in  a 
tapped  plate  attached  to  the  pattern. 

Lift  off — to  remove  a  portion  of  a  mold  after  ram- 
ming up. 

Loam. — Loam  sand  is  a  mixture  of  sand,  clay  and 
venting  material  such  as  horse  manure,  that  gives  a  firm, 
hard,  but  open-grained  body  when  dry.  The  mixture 


220  GLOSSARY 

must  be  regulated  by  the  class  of  castings  for  which  the 
loam  is  to  be  used. 

Loam  board — a  board  the  edge  of  which  is  profiled 
to  a  sectional  form  of  a  mold  which  it  is  to  strike  up.  It 
is  swept  around  a  vertical  bar  to  which  it  is  bolted. 

Loam  mold — a  mold  constructed  of  loam. 

Loam  plate — a  plate  of  iron  cast  in  an  open  mold 
and  studded  with  spikes  upon  which  the  brickwork  of 
a  loam  mold  is  built. 

Loose  piece — a  portion  or  projection  made  detach- 
able from  the  body  of  a  pattern  for  convenience  in 
molding. 

Melting  zone — a  space  above  the  tuyeres  in  a  cupo- 
la where  the  greatest  heat  is  obtained. 

Mold — the  matrix  or  reverse  form  of  a  pattern 
made  in  sand. 

Molding— the  process  of  forming  a  mold  in  which 
metal  is  to  be  cast. 

Molding  machine — any  machine  by  which  the  oper- 
ation, of  molding  is  performed  or  the  drawing  of  a  pat- 
tern is  made  safe  and  expeditious. 

Molding  sand — sand  used  for  the  purpose  of  form- 
ing a  mold,  and  possessing  the  quality  of  resisting  the 
pressure  of  molten  metal  as  well  as  the  heat.  It  also 
must  be  porous  or  open  when  compressed  in  order  to 
allow  the  free  escape  of  the  gases  generated  by  the 
heat  of  the  metal. 

Nowel — the  bottom  portion  of  a  mold  when  in  po- 
sition to  cast.  Commonly  called  drag. 

Old  sand — sand  which  has  been  used  for  the  pur- 
pose of  molding  until  it  becomes  old,  black  and  burnt 
from  contact  with  the  molten  metal. 

Open  sand  molding — molds  formed  in  the  floor  of 


GLOSSARY  221 

the  foundry  and  having  no  cope  or  covering.  Only  cast- 
ings having  one  flat  side  or  surface  can  be  formed  this 
way.  The  mold  must  in  all  cases  be  perfectly  leveled. 

Parting  sand — sand  used  for  the  purpose  of  pre- 
venting two  parts  of  a  mold  from  uniting.  It  causes 
the  sand  to  part  when  the  flask  is  opened  after  ram- 
ming. Sharp  sand  or  burned  core  sand  is  commonly 
used. 

Patching — the  process  of  repairing  a  mold  after  the 
pattern  has  been  removed  from  the  sand. 

Pattern — a  model  from  which  to  form  a  mold.  Its 
impression  in  the  sand  forming  a  mold  in  which,  to  pour 
molten  metal  to  form  a  casting. 

Peeling. — A  casting  is  said  to  peel  when  the  mold- 
ing sand  and  iron  do  not  fuse.  After  the  casting  has 
cooled  the  surface  of  the  metal  is  left  smooth  and  free 
from  sand. 

Pit  molding — forming  a  mold  in  a  pit  dug  in  a  foun- 
dry floor.  Light  pit  molding  is  usually  of  green  sand. 

Plate  anchor — the  anchor  used  in  a  pulley  anchor 
having  plates  to  cover  the  surfaces  between  the  arms. 

Plate  molding — dividing  the  pattern  at  its  centre 
and  placing  each  half  on  one  side  of  a  parting  board 
which  is  provided  with  pin  holes  corresponding  with 
the  pins  of  interchangeable  flasks.  The  drag  and  cope 
may  be  rammed  on  opposite  sides  of  the  board,  and 
after  the  board  has  been  removed  the  flask  may  be 
closed. 

Plumbago — a  mineral  consisting  chiefly  of  carbon. 
It  is  used  for  blacking  and  for  facing.  It  is  properly 
called  graphite,  but  often  called  black  lead. 

Pouring — the  emptying  of  the  molten  metal  from 
the  ladle  into  the  pouring  basin  or  gate  of  a  mold. 


222  GLOSSARY 

Pouring  basin —  a  reservoir  or  basin  formed  on  the 
cope  of  a  mold  to  receive  the  molten  metal  and  from 
which  it  flows  into  the  gate. 

Pulley  anchor — the  part  of  the  mold  of  a  pulley  be- 
tween the  arms  and  the  face  of  the  cope. 

Pulley  foot — a  cone  or  pyramid  placed  in  the  an- 
chor of  a  pulley  mold  for  the  purpose  of  ensuring  re- 
moving and  replacing  to  the  same  position.  The  pul- 
ley foot  may  be  separate  and  placed  in  the  anchor 
while  ramming,  or  it  may  be  a  part  of  the  anchor,  as  in 
a  plate  anchor. 

Rammer — a  tool  used  for  the  purpose  of  ramming 
the  sand  in  the  flask  and  around  the  pattern.  The 
rammer  is  usually  made  of  iron.  One  end  is  called  the 
pein  and  the  other  the  butt.  The  pein  end  is  rectangu- 
lar in  section  and  the  butt  end  is  round  and  flat. 

Rapping — the  process  of  loosening  the  pattern  from 
the  sand  while  yet  in  the  mold.  A  bar  is  inserted  in  the 
pattern  and  is  rapped  sidewise  in  every  direction  until 
the  sand  compresses  and  is  free  from  the  pattern,  after 
which  the  pattern  may  be  easily  withdrawn. 

Rapping  bar — a  bar  of  iron  either  pointed  or 
threaded  at  one  end  to  be  inserted  into  a  pattern  for 
the  purpose  of  rapping. 

Rapping  hole — a  hole  bored  in  a  pattern  or  in  a  rap- 
ping plate  let  into  the  pattern  to  receive  the  rapping  bar. 

Rapping  plate — an  iron  plate  screwed  to  or  let  into 
a  pattern  having  a  hole  to-  receive  the  rapping  bar. 

Reverse  mold — a  dummy  mold  on  which  a  portion 
of  an  actual  mold  is  to  be  rammed. 

Riddle — a  sieve  for  sifting  sand  for  the  purpose  of 
molding. 

Riser — an  opening  from  the  mold  to  the  top  of  the 


GLOSSARY  223 

flask  through  which  gases  may  escape  and  the  surplus 
metal  rise  above  the  upper  surface  of  the  casting. 

Runner — a  channel  cut  in  the  sand  to  conduct  the 
metal  from  the  pouring  basin  to  the  gate. 

Sand  sifter — a  mechanical  device  for  the  purpose  of 
sifting  sand. 

Scabbed  castings. — Scabbed  castings  are  those  on 
the  surface  of  which  rough  and  uneven  projections  ap- 
pear. Scabs  occur  from  various  causes,  such  as  im- 
perfect venting,  improper  ramming,  unsuitable  ma- 
terial, too  rich  facing  sand,  excess  of  moisture,  etc. 

Scrap — that  which  is  of  no  use  in  its  present  form. 
The  old  castings  which  are  only  good  for  the  metal  in 
them,  or  castings  which  can  not  be  used,  are  called  scrap. 

Sea  coal. — Sea  coal  is  ordinary  bituminous  coal. 
When  pulverized  and  mixed  with  molding  sand,  it  is 
called  sea  coal  facing. 

Shrinkage — contraction  of  metal  while  cooling 
after  casting. 

Shrink-holes — openings  in  the  surface  or  in  the  in- 
terior of  a  casting  caused  by  the  shrinkage  of  the  metal 
in  cooling. 

Sinking  head — the  prolongation  upon  a  casting  ver- 
tically to  supply  metal  to  replace  shrinkage.  The  ex- 
cess length  is  cut  off,  leaving  the  desired  casting, 

Skeleton  core  box — a  frame  or  skeleton  in  which  to 
form  a  core  without  a  full  core  box.  Skeleton  core  boxes 
are  commonly  used  in  forming  one-half  of  a  round 
core  by  means  of  a  strike  stick. 

Skim  gate — an  arrangement  of  gates,  runners,  and 
risers  which  will  effect  the  separation  of  the  impurities 
before  the  metal  enters  the  mold. 

Skimmer — a  bar  of  iron  usually  bent  to  the  shape 


224  '     GLOSSARY 

of  the  letter  L  at  one  end  for  the  purpose  of  prevent- 
ing the  slag  and  dirt  from  following  the  metal  as  it 
flows  from  the  ladle  to  the  pouring  basin  of  a  mold. 

Skimming — the  holding  back  of  the  slag  and  dirt 
on  the  surface  of  molten  metal  while  being  poured  from 
the  ladle  into  the  mold. 

Skin-drying — the  process  of  drying  the  face  of  a 
mold. 

Slag — the  refuse  from  the  cupola,  caused  by  im- 
purities of  the  metal  and  fuel  as  well  as  by  the  fused  com- 
pounds .  of  the  silica  and  alumina  in  the  lining  and 
daubing. 

Slag  hole — a  port  hole  in  a  cupola  slightly  below 
the  level  of  the  tuyeres  for  the  purpose  of  tapping  out 
the  slag  before  tapping  the  iron. 

Sleeking. — See  Slicking. 

Slick — a  tool  used  for  smoothing  the  surface  of  a 
mold.  An  ordinary  trowel  may  be  used  for  a  slick. 

Slicking — smoothing  and  finishing  the  surface  of  a 
mold  with  a  trowel  or  slicking  tool.  Sometimes  spelled 
sleeking. 

Sling — a  device  made  of  iron  or  of  rope  for  the  pur- 
pose of  handling  flasks  or  weights.  The  sling  is  used  to 
connect  the  .crane  to  a- weight  or  to  the  trunnion  of  a 
flask. 

Snap  flask — a  small  flask  used  in  Vr.ch  molding 
having  a  hinge  at  one  corner  and  a  lat'.li  at  the  diagonal 
corner. 

Soldiers — strips  of  wood  used  by  the  molder  to 
strengthen  or  to  anchor  bodies  of  sand. 

Socket — the  base  for  supporting  the  spindle  in  a 
sweep  mold.  See  Foundation  plate. 

Spongy. — A  casting  is  spongy  when  honeycombed 


GLOSSARY  225 

by  blow-holes.    The  centre  of  a  casting  may  be  spongy 
from  shrinkage  of  the  metal  in  solidifying. 

Spout — a  box  or  gutter  lined  with  clay  to  con- 
duct the  molten  metal  from  the  tapping  hole  to  the 
ladle. 

Spray  can — a  can  fitted  with  a  blow-pipe  or  bellows 
so  that  the  liquid  in  the  can  may  be  forced  out  in  a 
spray  or  mist. 

Sprue — the  casting  formed  in  the  gate  of  a  mold. 
See  Gate. 

Staking — the  setting  of  the  cope  on  a  pit  in  the 
mold  by  means  of  stakes. 

Stopping  off — the  process  of  filling  up  a  portion  of 
the  mold  which  is  not  desired  to  be  cast. 

Stopping-off  piece — a  piece  used  as  a  guide  or  tem- 
plate in  stopping  off.  A  stop-off  piece  is  a  duplicate  of 
the  desired  casting  at  the  point  stopped  off  on  the  pat- 
tern. 

Stopping  over — filling  up  with  sand  the  space  over 
a  core  placed  in  a  print  pocket. 

Straining — the  distortion  of  a  mold  by  the  pressure 
of  the  metal,  usually  caused  by  insufficient  ramming  of 
the  sand. 

Strike  stick — a  straight  edge  or  form  beveled  at  its 
edge  for  the  purpose  of  cutting  the  sand  or  loam  in 
building  up  a  mold  or  core. 

Stripping  plate — the  plate  which  holds  the  sand  in 
place  while  the  pattern  if  being  drawn. 

Strong  sand. — Molding  sand  is  called  strong  when 
it  contains  clay  and  when  upon  drying  it  becomes  hard 
and  will  not  crumble. 

Swab — a  substitute  for  a  brush  for  dampening  sand 
in  a  mold  or  around  a  pattern  before  it  has  been  removed 
from  the  sand.  Swabs  are  usually  made  of  hemp. 


226  GLOSSARY 

Swabbing — the  dampening  with  a  swab  of  the  joint 
edges  or  interior  sections  of  a  mold  for  the  purpose  of 
strengthening  the  sand  and  causing  it  to  be  more  plasti'; 
and  coherent. 

Sweep — a  board  having  the  profile  of  a  desired 
mold.  A  sweep  must  be  attached  to  a  spindle  and  re- 
volved around  the  spindle  to  give  the  mold  the  proper 
form. 

Tap  hole — the  hole  through  the  breast  of  a  cupola 
through  which  the  metal  flows. 

Tapping — opening  the  port  of  a  foundry  cupola  for 
the  purpose  of  allowing  the  metal  to  flow  into  the  ladle. 

Tapping  bar — a  long  bar  of  iron  pointed  at  one  end 
and  having  a  loop  at  the  other  to  serve  as  a  hand  hold. 
It  is  used  for  the  purpose  of  opening  the  tap  hole  in  a 
cupola  to  allow  the  metal  to  flow  out. 

Tempering  sand — the  process  of  dampening  and 
mixing  the  sand  preparatory  to  ramming  a  mold. 

Test  bar — a  bar  of  iron  cast  for  the  purpose  of  test- 
ing the  strength  of  the  metal. 

Trammel- — another  name  for  a  beam  compass. 

Traveling  crane — an  apparatus  arranged  on  over- 
head tracks  and  so  constructed  as  to  move  a  load  in 
any  direction. 

Trowel — a  tool  similar  to  a  mason's  trowel,  used  in 
slicking,  patching,  and  finishing  a  mold.  Trowels  are  of 
various  shapes  and  sizes. 

Tucking — compressing  the  sand  with  the  fingers 
under  flask  bars  or  around  gaggers  or  soldiers  where 
the  rammer  can  not  be  used. 

Turning  over — the  operation  of  inverting  the  drag 
of  a  mold  with  the  pattern  in  the  sand.  The  top  and 


GLOSSARY  227 

bottom  are  covered  with  boards,  clamped  up,  and  turned 
over. 

Turn-over  board — the  board  upon  which  a  pattern 
is  placed  while  ramming  up  the  drag  of  a  mold. 

Tuyeres — the  openings  which  admit  the  air  blast 
to  the  interior  of  a  cupola  or  blast  furnace. 

Vents — any  means  provided  for  the  escape  of  gases 
or  of  steam  generated  by  contact  of  molten  metal  with 
cores  or  molding  sand. 

Vent  gutter — a  groove  or  an  opening  cut  in  the 
sand  to  conduct  the  gases  away  from  the  vents. 

Venting — the  process  of  making  vent  holes  or  open- 
ings in  the  mold  by  means  of  a  vent  wire,  or  otherwise, 
to  allow  the  gases  to  escape  while  casting. 

Vent  strings — strings  used  for  the  purpose  of  vent- 
ing crooked  cores  when  wires  or  rods  could  not  be  em- 
ployed without  damaging  the  core.  Sometimes  wax 
strings  are  used  and  melted  out  in  drying  the  core. 

Vent  wire — a  small  rod  or  wire  used  in  forming  a 
vent. 

Weak  sand — sand  having  a  very  small  percentage 
of  clay,  thus  having  but  little  strength  at  the  usual 
temper  and  hardness. 

Wedges — small  V-shaped  pieces  for  the  purpose  of 
blocking  under  a  clamp  or  over  a  chaplet.  Wedges  may 
be  of  wood  or  of  iron. 

Wet  blacking. — See  Black  wash. 

Wind  jacket — the  chamber  surrounding  a  cupola 
into  which  the  air  is  forced  from  the  blast  pipes  and 
from  which  it  enters  the  tuyeres  leading  to  the  cu- 
pola. 


TABLES 


MELTING  POINTS  OF  DIFFERENT  BRANDS  OF  IRON 


Combined 
.Carbon 
Percentage 

Graphite 
Percentage 

Character 
of  Fracture 

Melting 
Point 
Deg.  F. 

Remarks 

i.  60 
4.67 

3-i6 

•03 

Gray 
White 

22IO 
2000 

Samples  cast 
from  same  ladle 

i-57 
4.20 

2.90 

.20 

Gray 
White 

2250 
1990 

Samples  cast 
from  same  ladle 

1.20 

3-90 

2.90 
.16 

Gray 
White 

22SO 
20OO 

Samples  cast 
from  same  ladle 

MELTING  POINTS  OF  SOLIDS 


Cast  Iron 

3477  deg. 

Lead 

6co  deg. 

Wrought  Iron        * 

3981  deg. 

Zinc 

74i  deg. 

Gold 

2587  deg. 

Cadmium 

602  deg. 

Silver 

1250  deg. 

Saltpetre 

600  deg. 

Steel 

2501  deg. 

Tin 

420  deg. 

Brass 

1897  deg. 

Sulphur 

225  deg. 

Copper 

2550  deg. 

Potassium 

135  deg. 

Glass 

2377  deg. 

Antimony 

95i  deg. 

Platinum 

3077  deg. 

Bismuth 

476  deg. 

METAL  ALLOYS     (values  represent  proportional  parts) 


Copper     Tin         Zinc       Lead   Ant'm'y  Bism'th 

Brass  valves 

9 

i 

•50 

'     bearings 

10 

1.50 

.50 

Bell  metal 

15 

5 

Yellow  Brass 

'36 

2.50 

17          !     2.50 

Gun  metal 

9 

i 

Fine  solder 

i 

I 

Plumber's  solder 

i 

2 

Cast  Iron        " 

2 

I 

Babbitt  metal 

i 

10 

i 

Metal  to  expand  in  cooling 

9 

2 

I 

Type  metal 

9 

I 

Hard  Bronze  for  lathe  bearings 

80 

20 

230 


TABLES 


CHILLED-ROLL  IRON 


1-1 

IH 
X    -2     ^     M 

bi 

C           en 

<D 

£.5  » 

c 
0    to 

11 

lUl 

u    g    «    <u 
rt    rt  -°  ^ 

•a  -a  -o 

1  §  § 

S|f 

t*      •   TJ 

c    cr  c 

-S    o> 

<->    J3 
CU     <y 

1° 

31*5  -a 

y  73   o  .S 

*T  8. 

v* 

S«  v,  o 

c/3  «   a 

jj 

I 

1/8 

1.140 

3-  2^0 

1.  021 

3.i83 

.105 

2 

i« 

1.655 

9.500 

2.151 

4.417 

.090 

3 

i  15-16 

1.968 

15.250 

3-042 

5-013 

.085 

GUN  CARRIAGE  IRON 


I 

1/8 
1^8 
I    15-16 

1.  122 

1.664 

1.859 

2.780 
9.250 
i  i  .  820 

.988 
2-174 
2.714 

2.812 
4.264 

4-355 

.100 
.110 
.100 

CAR  WHEEL  IRON 

7 
8 
9 

1/8 
Itt 
I    15-16 

1.  174 
1.690 
2.008 

2.200 
8.100 
13.500 

1.082 
2.244 
3.167 

2.033 
3.6io 
4.263 

.053 

.070 

.072 

HEAVY  MACHINERY  IRON 

IO 

II 

12 

1/8 
1^8 
I    15-16 

1.187 
1.705 

2.001 

2.800 
7.100 
11.900 

1.106 

2.282 
3.M3 

2.530 
3.1X1 

3.786 

.092 
.072 
.079 

STOVE  PLATE  IRON 

13 
14 

15 

1/8 

iH 

i  15-16 

I.I82 

1-745 
2.047 

2.500 
6.050 
9.900 

1-097 
2.391 
3-288 

2.288 
2-530 
3.011 

.117 

.078 

.081 

BESSEMER  IRO.>I 


16 

1/8 

I.I75 

2.150 

1.084 

1-983 

.100 

17 

I« 

1.698 

5.500 

2.263 

2.430 

.100 

18 

I    15-16 

1.991 

8.900 

3-  112 

2.860 

.085 

19 

i  in.  square 

•994 

1-757 

.988 

1.778 

.150 

CHEMICAL  ANALYSIS  OF  IRONS  DESCRIBED  ABOVE 


5 

M 

T3 

c 

0 

h 

3 

0) 

c 
rt 

0 
43 

.5  | 

'Z   c 
'2   % 

—   c 
2  J 

Class  of  Iron 

3 

Q. 

bo 

c 

d, 

C     *^ 

a* 

o  •£ 

P-H      C? 

t/3 

(/) 

rt 

2 

0   '^ 

*K     O 

CJ 

s 

PH 

U 

U 

Chill  iron 
Gun  metal 
Car  wheel 

.84 
•  73 
.78 

.071 

.059 
•  132 

.285 

.408 
.306 

•547 

.61 
•  76 
1.07 

2.45 
2-47 
2.36 

3.06 
3-23 

3  43 

General  machinery 
Stove  plate 
Bessemer  iron 

1.30 
2.47 
1.52 

•053 
.094 
.059 

.224 

.265 
.326 

^083 

•58 
.19 
•49 

3-31 
4.00 

3-73 

3.89 
4.19 

4.22 

TABLES 


231 


SIZE  AND  CAPACITY  OF  FOUNDRY  LADLES 


I 

Capacity 
in 
pounds 

Inside  dimensions 

Al'wsfordaub'g 

•Vl'wsat 
op  over 
cap'c'ty 
ins. 

Diameter 

Depth 
in. 

at    bot- 
tom in. 

at  sides 
in. 

Top    in. 

Bottom  in. 

5o 

8.25 

6.25 

6 

.50 

•  375 

.50 

rn 

100 

10 

9 

9.50 

i 

•50 

5o 

v 

3 

150 

ii 

10 

10.50 

i 

•50 

50 

is- 

200 

12 

ii 

11.50 

i 

.50 

5o 

H 

250 

13 

12 

12.50 

i 

.50 

.  £o 

en    ti 

300 

14 

12.50 

13 

i 

.50 

.50 

c 

350 

14.50 

13 

13.50 

i 

.50 

•  50 

400 

15.50 

M 

14.50 

1.25 

•75 

•75 



BOO 

16.50 

15 

15.50 

1.25 

•75 

•75 

600 

17.50 

16 

17 

1.25 

•75 

•75 

700 

18 

16.50 

17.50 

1.25 

•75 

•75 

0 

800 

18.50 

17 

18 

1.25 

•75 

•75 

V 

3 

IOOO 

20.50 

18.50 

19.50 

1.50 

1200 

21.50 

19.50 

21 

1.50 

5T 
& 

I5OO 

23 

21 

22 

1.50 

re 

2000 

25.50 

23.50 

24.50 

1.50 

•50 

250O 

27 

25 

26 

1-50 

•5o 

3000 

28.50 

26 

27.50 

1.50 

2.50 

3500 

30 

27.50 

29 

1.50 

2.50 

4000 

31.50 

28.50 

30 

1.50 

3 

&3 

45°° 

33.50 

30.50 

32 

2 

•50 

3 

3 
ft 

5000 

34.50 

31 

33 

2 

.50 

3 

sr 

6000 

36.50 

33 

35 

2 

.50 

3 

O- 

8000 

40.50 

36.50 

38.50 

2.50 

•75 

3 

*8  • 

10,000 

43.50 

39 

4i 

2.50 

•75 

3-50 

»  g. 

12,000 

45.50 

4i 

43-50 

2.50 

•  75 

3-50 

5 

14,000 

48 

43 

45.50 

2.50 

•75 

3-50 

1 

16,000 

50 

45 

47-50 

2.50 

•75 

3-50 

c 

18,000 

52 

46.50 

49 

2.50 

•75 

3-50 

5' 

srq 

20,000 

53.50 

48 

50.50 

2.50 

•75 

3-50 

24,000 

57 

5i 

54 

2.50 

3-50 

SHRINKAGE  OF  CASTINGS  (approximate  values  only) 


Metal 


Inches  per  lineal  foot 


Cast  Iron 

Brass 

Tin 

Zinc 

Steel 


.125 

.1875 


232 


TABLES 


WEIGHTS  OF  CASTINGS  FROM  PATTERNS  WHERE  No 
CORES  ARE  USED 


will  weigh  when  cast  in 

A  pattern,    weigh- 
ing i  lb.,raade  of 

Cast    Iron 

Zinc 

Copper 

YTw  Brass 

Gun    Metal 

* 

Ibs. 

Ibs. 

Ibs. 

Ibs. 

Ibs. 

Mahogany,  Nassau 

10.7 

10.4 

12.8 

12.2 

12.5 

"        Honduras 

12.9 

12.7 

15-3 

I4.6 

15.0 

Spanish 

8-5 

8.2 

10.  I 

9.7 

9-9 

Pine,      Red 

12.5 

12.1 

14.9 

14.2 

14.6 

White 

16.7 

16.  I 

19.8 

19.0 

19-5 

"      Yellow 

14.1 

13-6 

16.7 

16.0 

16.5 

Oak 

9.0 

8.6 

10.4 

10.  1 

10.9 

WEIGHTS  OF  ONE  CUBIC  FOOT  OF  METALS  WITH  THEIR 
TENSILE  STRENGTH 


Metal 

Weight  of  i  cu. 
ft.  in  pounds 

Tensile    strength    per 
sq.  in.  in  pounds 

Cast  Iron 
Ordinary  Brass 
Wrought  Iron 
Hard  Structural  Steel 
Aluminum 

450 
525 
480 
490 
166.5 

16,500 
36,000 
50,000 
78,000 
26,800 

WEIGHT  IN  POUNDS  OF  ONE  CUBIC  INCH  OF  DIFFERENT  METALS 


Brass  (average) 

•  3023 

Zinc,  cast 

.26 

Bronze 

.306 

Antimony 

.242 

Copper,  cast 

'     .3135 

Bismuth 

•355 

Gold,  pure 

.6965 

Manganese 

.289 

Iron,  cast 

.2622 

Silver 

•  378 

Iron,  wrought 

.282 

Platinum 

•735 

Lead,  cast 

.415 

Cadmium 

.312 

Steel 

.281 

Potassium 

.031 

Tin,  cast 

.263 

MIXTURES  FOR  PHOSPHOR-BRONZE  BEARING  METAL 


* 

Number  of 

Copper 

Lead 

Tin 

Phosphorus 

* 

mixture 

per  cent. 

per  cent. 

per  cent. 

per  cent. 

i 

79-0 

10.  0 

10 

I.O 

2 

79-7 

9-5                          10 

.8 

79-7 

10.  0                                    10 

.3 

TABLES 


233 


SIZE  AND  CAPACITY  OF  CRUCIBLES 


Number 
of 
crucible 

Outside 
height 
inches 

Greatest 
outside    di- 
ameter   in. 

Capacity  in 
molten 
metal     Ibs 

i 

3-50 

3 

3 

2 

4 

3-25 

6 

3 

4.625 

3-75 

9 

4 

5.125 

4-25 

12 

5 

6 

4.625 

15 

6 

6.50 

5.125 

18 

8 

7.25 

5.875 

24 

10 

8.25 

6.25 

30 

12 

8.625 

6.50 

36 

14 

9.125 

7.25 

42 

16 

9.625 

7-75 

48 

18 

10 

8.125 

54 

20 

10.625 

8.625 

60 

25 

11.125 

9 

75 

3o 

11.75 

J7L_ 

90 

35 

12.25 

9-75 

105 

40 

12.625 

9-875 

120 

45 

13 

10.50 

135 

5o 

13-73 

10.75 

150 

60 

14.125 

11.25 

180 

70 

14-75 

11-75 

210 

80 

15.50 

12.50 

240 

IOO 

16.125 

11 

300 

vA 


ft  A 
r  THE 


{jt      inc. 

UNIVERSITY 


• 


INDEX 


Bedding   in,    69. 

Blow-holes  and  shrink-holes,  42. 

Brass,  molding  of,  198;  founding 
of,  200;  melting  furnace  .for, 
201;  same  for  fuel  oil  or  gas, 
206. 

Burning  on  or  casting  on,  43. 

Castings,  feeding  of,  27;  chilled, 
173;  malleable,  177;  cleaning 
of,  180;  steel,  194. 

Cast  iron  alloys,  206-207. 

Chaplets,  described,  31;  setting 
and  wedging  of,  34. 

Clamping  or  weighting  of  cope 
and  cores,  38. 

Columns,    molding-  of,    102. 

Compressed  air,   184. 

Coping   out,    65. 

•Cores,  setting  and  venting  of, 
29,  77;  cover,  92;  described, 
110;  ramming  of,  112;  wires 
and  rods  for,  112;  baking  or 
drying  of,  115;  pasting  of,  128; 
nearly  submerged,  132. 

Core  anchors,   130. 

Core    barrel,    123. 

Core  box,  124;  skeleton  core  box, 
126. 

Core-making  machines,    138. 

Core  mixtures,  J20;  core  blacking 
mixtures,  122. 

Core  ovens,  116. 

Core  plates,  130. 

Cupola,  preparing  of,  157;  tap- 
ping out  and  stopping  up  of, 
162. 


Flasks,  6. 

Fly-wheels,    methods   of   casting, 
148. 


Follow -board,   45. 

Foundry  blowers,   170. 

Foundry   ladles,   167. 

Furnace  cupola,   153;   reverbera- 

tory,    169;    brass    melting,    201; 

same  for   fuel   oil  or  gas,   206. 


Gaggers,   20. 

Gears,  molding  of,  106. 

Hay    rope    machines,    122. 

Loam   mixtures,    151. 
Loam  molding,  150. 


Molding,  bench,  44;  plain,  53; 
with  divided  pattern,  61;  open 
sand,  72;  of  columns,  102;  of 
gears,  106;  pit,  143;  loam,  150; 
brass,  198. 

Molding  machines,   47. 

Molds,  venting  of,  11;  parting  of, 
14;  gating  of,  15;  patching  of, 
24;  stopping  off  of,  26;  crush- 
ing of,  40;  match  for  a,  45;  dry 
sand,  137;  finishing  dry  sand, 
139;  blacking  dry  sand,  139; 
drying  dry  sand,  140. 


Nailing  or   rodding,    23. 

Pneumatic      chipping      hammer, 

184. 

Pneumatic  crane,   184. 

Pneumatic  hoist,   189. 
Pneumatic      molding      machine, 

184. 

Pneumatic  sand   rammer,    184. 

Pneumatic  sand  sifter,  184. 


236 


INDEX 


Pneumatic    shaker,    188. 
Pouring   basins,    20. 
Pulley  anchors,   98. 
Pulley  rings,   96. 

Risers,  16. 


Sand,  molding,  1;  tempering  of, 
1;  cutting  over  of,  1;  riddling 
of,  3;  facing,  4;  ramming  of, 
9;  parting,  15.  . 

Sand  blast  machine,  188. 

Sand  crusher,   192. 


Sand    mixers,     191;     centrifugal, 

191. 

Sand  sifter,   rotary,   189. 
Shrinkage,   41. 
Skim   gates,   17. 
Soldiers,   22. 
Steel,   casting  of,  194. 
Sweeps  and  spindles,  145. 

Three-part  work,    79. 
Tools,  molders',  8. 
Tumbling  barrels,  180. 

Vent  gutters,    134. 


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DEC161WO 


LD  21-100m-7,'40  (6936s) 


YC  955V3 


